The Helite Canisters have a screw end for Helite Air Jackets (including old Jackets manufactured by Helite too under other brand names). If you are unsure of the manufacturer please look inside the left handside of your air jacket. Make savings by buying in bulk on this site but for individual canisters please buy from our other website www.helite.co.uk To guarantee a proper functioning of the airbag system, it is of crucial importance to mount the trigger system correctly. The order must always be: piston, key-ball (notch on piston to fit the ball in), spring and bearing cap. The needle of the piston must point in the direction of the cartridge, the key-ball has to fit in the notch of the piston. Caution: Never put the key-ball between spring and piston, this disables the system to trigger. Available in minimum quantity of 3 online (if collecting from office or at shows no minimum!) Please see the instruction manual supplied with the jacket for help changing canisters The CO2 canisters have a long life span but we do recommend a yearly check. The check consists of weighing your canister and making sure it is approximately (+/-3g) equivalent to the weight written on your canister. Must be stored in temperatures between 0ºC - 45ºC.If stored under 0ºC, warm up before use or replace with a warmer cartridge. Do not leave full cartridges in the car in high temperatures If rust or other corrosive marks appear on the outer surface of the canisters change them immediately and discard. Only install gas canisters of the same size and content as sold with the jacket. Postage to UK mainland only. Jacket Size Cartridge needed Canister Weight (gram) Original Child S, M, Air Shell L 50 cc btw 150 - 155 g Original Child L, Adult XS, S, M, L, XL Air Shell Adult XS - XL 60 cc btw 180 - 185 g