Scuba O-Ring Sizes

If you’re looking to buy replacement O-Rings, stick to FKM (Viton) as the material. If you buy from non-scuba sources, it’s really not that expensive and does last a lot longer.

SCUBA Application SealNameGewinde
Standard DIN Regulator/Valve
(Nearly all DIN regulators)
Duro: NBR 70/90, FPM 75
BS1806-
112
5/8"
Apeks DIN Regulator/Valve
Duro: NBR 70, FPM 70
BS1806-
111
5/8"
HP Port/Hose
Manifold and Manifold Port Plugs
Duro: NBR 90, FPM 90
BS1806-
012
7/16" UNF
LP Port/Hose (3/8" UNF)
Duro: NBR 70, FPM 70
BS1806-
011
3/8" UNF
HP swivel
Duro: NBR 90, FPM 90
BS1806-
003
1/16"

If your looking for more details, checkout Scuba Doctor.