The Lifejacket firing cartridge activates when there is contact with water to inflate the lifejacket bladder. Suitable for all automatic lifejackets fitted with UM MK5 and MK5i inflators.  The cartridge is stamped with the expiry date and should be replaced when this is reached.

The cartridge contains a paper element which when it comes into contact with water releases the spring inside the cartridge, this pushes the plunger forward in turn pushing a cutter into the Co2 cylinder allowing the Co2 to enter the lifejacket bladder to inflate.