RTS Zinc Coated CO2 Cylinder These cylinders fit most lifejackets and are 1/2″ UNF Thread. This is the norm on European lifejackets. CO2 Cylinders do not have an expiry date. Each cylinder is able to fully inflate your lifejacket and the correct size should be used. Twin chamber lifejackets are therefore fitted with pressure release valves so that if and when both cylinders fire together, the excess CO2 is released.
