Scuba Cylinder Specifications

Water volume, working pressure, weight, and buoyancy for common aluminum and steel scuba cylinders.

Buoyancy is in sea water with a valve fitted: negative sinks, positive floats. Free gas is the ideal water volume × working pressure estimate; manufacturers rate slightly less. Check your own cylinder's stamp and data sheet before planning gas or weighting from these figures.

aluminum cylinders

Water volume, working pressure, approximate free gas, empty weight, and buoyancy full and empty for aluminum scuba cylinders.
Cylinder	Water volume	Working pressure	Approx. free gas	Empty weight	Buoyancy full	Buoyancy empty
AL80Recreational single tank (warm water, training, sidemount) Brands and source notes Luxfer, Catalina, Thunderbird. Standard rental tank globally; becomes positively buoyant near end of dive. Weight and buoyancy from the Luxfer LAL80 sheet (full -0.80 kg, +1.54 kg at 500 psi, in sea water with valve); empty and at-50-bar are derived from the 500 psi row.	11.1 L	207 bar3,000 psi	2,296 L81 cu ftrated 80 cu ft	14.3 kg31.5 lb	−0.8 kg−1.8 lb	+2.0 kg+4.4 lb
AL 12LRecreational single tank (Asia, some EU regions) Brands and source notes Luxfer, Various Asian manufacturers, Some EU brands. Common in Asian dive markets; larger and heavier than AL80. Weight and water volume from the Luxfer P3080V (12.0 L, 16.5 kg, 204 mm; Luxfer scuba spec sheet 2022, which prints no buoyancy). Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	12 L	200 bar2,901 psi	2,400 L85 cu ft	16.5 kg36.4 lb	−1.4 kg−3.1 lb	+1.4 kg+3.1 lb
AL72Recreational single tank (smaller divers, shorter dives) Brands and source notes Luxfer, Catalina. Good option between AL63 and AL80; popular for travel and sidemount.	10 L	207 bar3,000 psi	2,068 L73 cu ftrated 72 cu ft	13.0 kg28.7 lb	−1.0 kg−2.2 lb	+1.5 kg+3.3 lb
AL63Small divers, short recreational dives Brands and source notes Luxfer, Catalina, Thunderbird. Popular with small-frame divers or kids; lighter but same diameter as AL80. Weight and buoyancy from the Luxfer LAL63 sheet (full -1.1 kg, +0.77 kg at 500 psi, in sea water with valve).	9 L	207 bar3,000 psi	1,862 L66 cu ftrated 63 cu ft	12.2 kg26.9 lb	−1.1 kg−2.4 lb	+1.2 kg+2.6 lb
AL50Stage / deco for light gas Brands and source notes Luxfer, Catalina, Thunderbird. Compact stage/deco bottle; manageable for warm-water tech dives. Weight and full buoyancy from the Luxfer LAL50 sheet (9.7 kg; full -1.13 kg in sea water with valve). Empty and at-50-bar are computed from the weight and water volume: the sheet's +0.36 kg at 500 psi sits 1.49 kg above its full row, more than the 1.38 kg of air 6.9 L holds between those pressures, so it cannot be right together with the full row.	6.9 L	207 bar3,000 psi	1,427 L50 cu ftrated 50 cu ft	9.7 kg21.4 lb	−1.1 kg−2.4 lb	+0.4 kg+0.9 lb
AL40Stage / deco / O₂ bottle Brands and source notes Luxfer, Catalina, Thunderbird. Common oxygen bottle for deco; good trim when clipped to left side. Weight and full buoyancy from the Luxfer LAL40 sheet (6.9 kg; full -0.32 kg in sea water with valve). Empty and at-50-bar are computed from the weight and water volume: the sheet's +1.13 kg at 500 psi sits 1.45 kg above its full row, more than the 1.14 kg of air 5.7 L holds between those pressures, so it cannot be right together with the full row.	5.7 L	207 bar3,000 psi	1,179 L42 cu ftrated 40 cu ft	6.9 kg15.2 lb	−0.3 kg−0.7 lb	+0.9 kg+2.0 lb
AL30Pony / emergency Brands and source notes Luxfer, Catalina, Thunderbird. Pony bottle for emergency gas; small enough for travel or boat use. Weight and buoyancy from the Luxfer LAL30 sheet (full -0.68 kg, 0 kg at 500 psi, in sea water with valve).	4.3 L	207 bar3,000 psi	889 L31 cu ftrated 30 cu ft	5.6 kg12.3 lb	−0.7 kg−1.5 lb	+0.2 kg+0.4 lb
AL19Pony / bailout Brands and source notes Luxfer, Catalina, Thunderbird. Very small bailout bottle; close to neutral when empty. Water volume is Luxfer's true LAL19 figure (2.87 L), so its real-gas free gas reads a touch over the marketed 19. Buoyancy from the Luxfer LAL19 sheet (full -0.60 kg, -0.05 kg at 500 psi, in sea water with valve).	2.87 L	207 bar3,000 psi	594 L21 cu ftrated 19 cu ft	3.6 kg7.9 lb	−0.6 kg−1.3 lb	+0.1 kg+0.2 lb
AL13Argon inflation / bailout Brands and source notes Luxfer, Catalina, Thunderbird. Usually mounted for drysuit argon inflation; rarely used for breathing gas. Buoyancy from the Luxfer LAL13 sheet (full -0.80 kg, -0.40 kg at 500 psi, in sea water with valve).	1.9 L	207 bar3,000 psi	393 L14 cu ftrated 13 cu ft	2.7 kg6.0 lb	−0.8 kg−1.8 lb	−0.3 kg−0.7 lb
AL100Longer rec single / big gas in warm water Brands and source notes Luxfer, Catalina, Thunderbird. High-capacity aluminum; tall and heavy. Weight and buoyancy from the Luxfer LAL100 sheet (full -2.10 kg, +0.86 kg at 500 psi, in sea water with valve).	13.2 L	228 bar3,300 psi	3,003 L106 cu ftrated 100 cu ft	18.6 kg41.0 lb	−2.1 kg−4.6 lb	+1.4 kg+3.1 lb

steel cylinders

Water volume, working pressure, approximate free gas, empty weight, and buoyancy full and empty for steel scuba cylinders.
Cylinder	Water volume	Working pressure	Approx. free gas	Empty weight	Buoyancy full	Buoyancy empty
Steel 12L 232Single tank EU cold water Brands and source notes Faber, Eurocylinders. Most common steel cylinder in Europe; stays negative. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 171 mm): 14.1 kg; the 2023 design (EN ISO 9809-1:2019) weighs 13.3 kg, about 0.7 kg more buoyant. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	12 L	232 bar3,365 psi	2,784 L98 cu ft	14.1 kg31.1 lb	−3.8 kg−8.4 lb	−0.6 kg−1.3 lb
Steel 12L 300Compact high-pressure single Brands and source notes Faber, Eurocylinders. Very dense; allows more gas but heavier topside and affects trim. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 171 mm): 18.0 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	12 L	300 bar4,351 psi	3,600 L127 cu ft	18.0 kg39.7 lb	−7.9 kg−17.4 lb	−4.0 kg−8.8 lb
Steel 15L 232Cold/long dives Brands and source notes Faber, Eurocylinders. Heavy but long bottom time; stays negative when empty. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 203 mm): 18.2 kg; the 2023 design weighs 16.7 kg (Faber press release, 14 April 2023), about 1.3 kg more buoyant. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	15 L	232 bar3,365 psi	3,480 L123 cu ft	18.2 kg40.1 lb	−5.1 kg−11.2 lb	−1.1 kg−2.4 lb
Steel 10L 232Small divers / twinset Brands and source notes Faber. Often used as twin 10s for balanced doubles in cold water. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 171 mm): 12.2 kg; the 2023 design weighs 11.5 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	10 L	232 bar3,365 psi	2,320 L82 cu ft	12.2 kg26.9 lb	−3.7 kg−8.2 lb	−1.0 kg−2.2 lb
Steel 10.5L 232Small divers / twinset Brands and source notes Faber, Eurocylinders. Popular compact steel; often used as twin 10.5s in Europe. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 178 mm): 12.9 kg; the 2023 design weighs 12.0 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	10.5 L	232 bar3,365 psi	2,436 L86 cu ft	12.9 kg28.4 lb	−3.9 kg−8.6 lb	−1.1 kg−2.4 lb
Steel 7L 232Deco/stage EU Brands and source notes Faber. Stage/deco bottle for cold water; remains negative throughout. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 140 mm): 8.5 kg; the 2023 design weighs 8.2 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	7 L	232 bar3,365 psi	1,624 L57 cu ft	8.5 kg18.7 lb	−2.7 kg−6.0 lb	−0.8 kg−1.8 lb
Steel 3L 300CCR oxygen / diluent Brands and source notes Faber, Eurocylinders. Standard 3L rebreather bottle; fits most CCR frames. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 100 mm): 4.8 kg; the 2023 design weighs 4.6 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	3 L	300 bar4,351 psi	900 L32 cu ft	4.8 kg10.6 lb	−2.7 kg−6.0 lb	−1.7 kg−3.7 lb
LP85Tech singles / doubles US Brands and source notes Faber. Popular cave/wreck tank; slightly positive when empty. Water volume and weight are the Faber LP85 sheet's (13.0 L, 14.2 kg). The sheet lists full -3.80 lb (-1.72 kg) and +2.32 lb (+1.05 kg) at 500 psi. Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	13 L	182 bar2,640 psi	2,366 L84 cu ftrated 85 cu ft	14.2 kg31.3 lb	−2.5 kg−5.5 lb	+0.4 kg+0.9 lb
LP95Tech doubles US Brands and source notes Worthington, PST. Cave/wreck doubles workhorse; roughly neutral when empty.	15 L	182 bar2,640 psi	2,730 L96 cu ftrated 95 cu ft	17.0 kg37.5 lb	−3.6 kg−7.9 lb	−0.2 kg−0.4 lb
HP100Popular US cold-water single Brands and source notes Faber. Good trim and buoyancy; favorite single for drysuit divers. Water volume and weight are the Faber FX100 sheet's (12.9 L, 15.6 kg; the sheet's 34.0 lb disagrees with its own kg figure). The sheet lists full -8.41 lb (-3.81 kg) and -0.59 lb (-0.27 kg) at 500 psi. The Worthington/PST X7-100 is a different cylinder (~11.6 L). Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	12.9 L	237 bar3,442 psi	3,061 L108 cu ftrated 100 cu ft	15.6 kg34.4 lb	−4.5 kg−9.9 lb	−1.0 kg−2.2 lb
HP120Long US single dives Brands and source notes Worthington, PST. Tall and heavy; lots of gas for single-tank tech or long rec dives. Weight and water volume from the Worthington X7-120 (15.3 L, 18.0 kg without valve; XS Scuba's Worthington sheet). The sheet lists -5.0 kg full and -0.9 kg empty with valve; physics sits 0.2 to 0.3 kg above. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	15.3 L	237 bar3,442 psi	3,631 L128 cu ftrated 120 cu ft	18.0 kg39.7 lb	−4.8 kg−10.6 lb	−0.6 kg−1.3 lb
HP117Tech singles / doubles US Brands and source notes Faber. Popular tech diving cylinder; good balance of capacity and trim. Water volume and weight are the Faber FX117 sheet's (15.0 L, 17.7 kg; the sheet's 37.6 lb is 17.05 kg and does not reproduce its own buoyancy rows). The sheet lists full -9.12 lb (-4.14 kg) and +0.35 lb (+0.16 kg) at 500 psi. Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	15 L	237 bar3,442 psi	3,560 L126 cu ftrated 117 cu ft	17.7 kg39.0 lb	−4.7 kg−10.4 lb	−0.6 kg−1.3 lb
HP130Very long cold dives Brands and source notes Worthington. Gas monster; heavy and long, often awkward for smaller divers. Weight and water volume from the Worthington X8-130 (16.0 L, 20.3 kg without valve; XS Scuba's Worthington sheet). Low confidence: the sheet's -0.9 kg empty and its 131.4 cu ft rating both point to about 16.7 L, so its volume or weight is off. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	16 L	237 bar3,442 psi	3,797 L134 cu ftrated 130 cu ft	20.3 kg44.8 lb	−6.2 kg−13.7 lb	−1.9 kg−4.2 lb
HP133Very long cold/deep single dives Brands and source notes Faber. Faber's largest single (sometimes called a 130). Heavy, and close to neutral when empty. Water volume and weight are the Faber FX133 sheet's (17.0 L, 19.4 kg). The sheet lists full -9.08 lb (-4.12 kg) and +1.45 lb (+0.66 kg) at 500 psi. Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	17 L	237 bar3,442 psi	4,034 L142 cu ftrated 133 cu ft	19.4 kg42.8 lb	−4.7 kg−10.4 lb	−0.1 kg−0.2 lb
CCR 2LCCR oxygen Brands and source notes Faber. Compact CCR O₂ bottle; easy to travel with and replace. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 100 mm): 2.6 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	2 L	200 bar2,901 psi	400 L14 cu ft	2.6 kg5.7 lb	−1.3 kg−2.9 lb	−0.8 kg−1.8 lb
CCR 3LCCR diluent Brands and source notes Faber. Standard diluent cylinder for most CCR units; often filled to 232 bar. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 100 mm): 3.6 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	3 L	200 bar2,901 psi	600 L21 cu ft	3.6 kg7.9 lb	−1.4 kg−3.1 lb	−0.7 kg−1.5 lb
HP80Short/shallower cold-water single or doubles Brands and source notes Faber. Compact steel; stays negative when empty. Water volume and weight are the Faber FX80 sheet's (10.2 L, 13.0 kg). The sheet lists full -8.05 lb (-3.65 kg) and -1.74 lb (-0.79 kg) at 500 psi. Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	10.2 L	237 bar3,442 psi	2,421 L85 cu ftrated 80 cu ft	13.0 kg28.7 lb	−4.3 kg−9.5 lb	−1.5 kg−3.3 lb
HP119Long cold-water single / big-gas doubles Brands and source notes Worthington, PST. High-capacity HP steel; stays negative. Weight and water volume from the Worthington X8-119 (14.8 L, 19.3 kg without valve; XS Scuba's Worthington sheet). Low confidence: the sheet's -0.9 kg empty and its 123 cu ft rating both point to about 15.6 L, so its volume or weight is off. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	14.8 L	237 bar3,442 psi	3,512 L124 cu ftrated 119 cu ft	19.3 kg42.5 lb	−6.3 kg−13.9 lb	−2.2 kg−4.9 lb
LP50Doubles/sidemount small-frame divers, cave/wreck Brands and source notes Faber. Popular small LP cylinder in the US; often overfilled in practice. Weight and water volume from the Faber LP50 (7.8 L, 8.6 kg; Faber LP spec sheet). Neither the Worthington nor the PST sheet lists an LP50. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	7.8 L	182 bar2,640 psi	1,420 L50 cu ftrated 50 cu ft	8.6 kg19.0 lb	−1.8 kg−4.0 lb	−0.1 kg−0.2 lb
LP72Vintage/ubiquitous US steel; still common on boats Brands and source notes PST, Worthington. Classic 2250 psi steel 72; slim profile; about neutral when empty. No sheet prints its water volume: 12.2 L is derived from the rated 71.55 cu ft at 2475 psi (real-gas air at 70 °F); the dataset's former 13.2 L was the error. The weight (13.7 kg) is the one that gives the published empty buoyancy (0 lb with valve; US Divers figures quoted on ScubaBoard); the 26 lb (11.8 kg) quoted beside it would make the cylinder +1.6 kg empty at that volume. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	12.2 L	155 bar2,250 psi	1,893 L67 cu ftrated 72 cu ft	13.7 kg30.2 lb	−2.3 kg−5.1 lb	0.0 kg0.0 lb
LP104US tech doubles workhorse Brands and source notes PST, Worthington. Large LP steel; heavy topside; remains negative when empty.	16.6 L	182 bar2,640 psi	3,022 L107 cu ftrated 104 cu ft	20.5 kg45.2 lb	−5.0 kg−11.0 lb	−1.5 kg−3.3 lb
LP108US tech doubles / big single Brands and source notes Faber. High-capacity LP steel; excellent for long tech dives and doubles. Water volume and weight are the Faber LP108 sheet's (17.0 L, 18.6 kg). The sheet lists full -5.0 lb (-2.27 kg) and +3.0 lb (+1.36 kg) at 500 psi. Buoyancy is computed from the weight and water volume, in sea water with a valve. Faber's sheet quotes buoyancy without a valve and its row labelled 500 psi is the empty figure (physics without a valve reproduces both rows within 0.17 kg), so the figures here sit about 0.6 kg lower than the sheet.	17 L	182 bar2,640 psi	3,094 L109 cu ftrated 108 cu ft	18.6 kg41.0 lb	−3.1 kg−6.8 lb	+0.6 kg+1.3 lb
Steel 18L 232Very long cold-water single Brands and source notes Faber, Eurocylinders. Common EU large single; heavy but lots of gas.	18 L	232 bar3,365 psi	4,176 L147 cu ft	21.0 kg46.3 lb	−5.5 kg−12.1 lb	−0.5 kg−1.1 lb
Steel 8.5L 232Small divers / twinset Brands and source notes ECS, Eurocylinders. Compact EU steel; often used as twin 8.5s. Faber makes no 8.5 L. Weight from a retailer listing of the ECS 8.5 L 232 bar 140 mm (11.0 kg, without valve); low confidence, other brands list 10.0 to 11.9 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	8.5 L	232 bar3,365 psi	1,972 L70 cu ft	11.0 kg24.3 lb	−3.7 kg−8.2 lb	−1.5 kg−3.3 lb
CCR 2.7LCCR oxygen/diluent (varies by unit) Brands and source notes Eurocylinders. A CCR bottle size seen on some frames. Weight unsourced; buoyancy computed from it. Faber's database lists no 2.7 L (its 100 mm sizes are 2, 2.5 and 3 L), and no other maker's sheet was found.	2.7 L	232 bar3,365 psi	626 L22 cu ft	3.9 kg8.6 lb	−2.0 kg−4.4 lb	−1.2 kg−2.6 lb
CCR 2L 232CCR oxygen/diluent Brands and source notes Faber. The EU-standard 232 bar rating of the compact CCR bottle. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 100 mm): 2.8 kg; the UK BS 5045-7 build weighs 2.6 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	2 L	232 bar3,365 psi	464 L16 cu ft	2.8 kg6.2 lb	−1.5 kg−3.3 lb	−1.0 kg−2.2 lb
CCR 3L 232CCR diluent Brands and source notes Faber, Eurocylinders. The EU-standard 232 bar rating of the common CCR diluent cylinder. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 100 mm): 3.8 kg; the UK BS 5045-7 build weighs 3.4 kg. Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	3 L	232 bar3,365 psi	696 L25 cu ft	3.8 kg8.4 lb	−1.6 kg−3.5 lb	−0.8 kg−1.8 lb
Steel 12L 200Sidemount / single tank EU Brands and source notes Faber. The light 200 bar Faber 12L; popular for sidemount in Europe, and slightly positive when empty. Weight from Faber's cylinder database (EN 1964-1 build, without valve, 171 mm): 12.0 kg. The 203 mm build weighs 13.6 kg (12.3 kg in the 2023 design). Buoyancy is computed from the weight and water volume, in sea water with a standard valve.	12 L	200 bar2,901 psi	2,400 L85 cu ft	12.0 kg26.5 lb	−1.6 kg−3.5 lb	+1.3 kg+2.9 lb

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