Supplied with light 

Fitted with a whistle - retro-reflective tapes for night-time recognition - a collar which folds back and a quick-fit crutch strap to prevent riding up.(except for Storm : no crutch strap and a single flotation block for chest/neck/head).
Self-righting capacity : these buoyancy aids are designed to help exhausted sailors turn safely on their backs this is the reason for the asymmetrical buoyancy distribution on some models.
Buoyancy is provided by closed cell polyethylene foam.