These are the FWE 16gm Threaded CO2 Cartridges – 6 Pack. These great quality Co2 cartridges are perfect for those emergencies that require fast tyre inflation. The FWE Threaded CO2 Cartridges only weight 58 grams each so you will barely notice one in your saddlebag. As this cartridge dispenses its air, it rapidly cools and becomes cold to the touch. FWE have included an anti-freeze foam sleeve to prevent the cold reaching your hands.