33g co2 cylinder for lifejacket Fits most adult 160N class automatic/manual lifejackets, eg our own Marinepool Inshore Automatic 160N lifejacket. Our lifejacket cylinders are the very best available, they are zinc coated to reduce rust. Approx length 138mm cubage:,45ml diameter,25.4mm screw thread , 1/2-20UNF fill pressure, 60 kgf/cm2