Thought it might help. XS seems to be the heaviest and not on the list, PST is usually the best on weight......... was wondering the same thing, why not PST.
STEEL CYLINDERS*
Manufacturer & Nominal Capacity Service pressure, psi Actual air capacity, cu. Ft. (at +10%) Outer diameter, in Length without valve, in Empty weight, lbs Buoyancy Empty, lbs (w/valve) Buoyancy Full, lbs (w/valve)
OMS 13 2400 +10% 13 3.9 14 5.9 -2.25 -3.31
OMS 20 2400 +10% 20 3.9 19.5 7.5 -1.5 -3
Heiser 45 2400 +10% 45 5.5 25.79 20.3 0.8 -2.575
PST LP 45 2400 +10% 45 5.5 23 19 -0.5 -3.7
OMS 45 2400 +10% 46 5.5 23 17.6 0 -4
OMS 50 2400 +10% 50 5.5 25.2 19.92 -1.5 -4.8
OMS 66 2400 +10% 66 7 21 25 -1.67 -5.15
PST 65 3500 67 7.25 16.75 26.2 -1.5 -6.4
PST MP 72 3300 72 6.9 20.75 30 -6 -11.4
Faber 72 3000+10% 72 6.75 20.5 28.7 -3.7 -8.45
Faber 80 2400 +10% 78 7.25 24 30 -1.7 -7.55
Faber 80 3180 +10% 80 7.25 19.88 32.5 -7.22 -13.22
PST E7-80 3442 PSI 80 7.25 20 28 -2.5 -8.5
PST LP-80 2400 +10% 80.6 7.25 24 34 -1 -7
PST 80 3500 82 7.25 19.75 28.6 -3.3 -9.3
OMS 85 2400 +10% 85 7 26 31 0 -6.7
Faber 95 2400 +10% 95 8 23.8 37.2 -1.2 -8.325
PST 95 2400 +10% 96.6 8 24.75 43.8 -3.3 -10.4
OMS 98 2400 +10% 98 8 24 38 0 -7.73
Faber 100 3180 +10% 100 7.25 24.01 38.7 -7.26 -14.76
PST E7-100 3442 PSI 100 7.25 24.12 33 -1 -8.5
PST 100 3500 102 7.25 23.94 34.1 -1.3 -8.8
Heiser 104 2400 +10% 104 8 27.36 47.4 -7.46 -15.26
PST 104 2400 +10% 106.2 8 26.88 46.4 -3.3 -11.27
OMS 108 (112) 2400 +10% 112 8 26 41 -1 -8
PST E8-119 3442 PSI 119 8 24 41 -2 -10.5
Heiser 120 3190 120 8.03 25.8 55 -17.82 -26.4
Faber 120 3180 +10% 120 7.25 28.64 48.3 -7.22 -16.22
PST E7-120 3442 PSI 120 7.25 28.25 38 0 -10.5
PST 120 3500 122.5 7.25 27.87 39.2 -1.3 -10.3
PST 120 2400 +10% 122.5 8 29.37 51.3 -1.7 -10.7
OMS 121 (125) 2400 +10% 125 8 29 45 0 -9.5
PST E8-130 3442 PSI 130 8 26.12 43 -1 -10.5
OMS 135 (131) 2400 +10% 131 8 30.7 47 0.75 -10.31
Heiser 140 3190 140 8.03 29.9 63 -18.04 -28.4
E8-149 3442 PSI 149 8 29.37 47.5 -1.7 -12.8
Heiser 190 4400 190 8.03 31.3 87 -46.86 -62.3