Lezyne 25-Gram CO2 Cartridges Inflating your tires with CO2 cartridges is easier and more convenient that carrying around a hand pump. This product comes in a pack of five so you'll never be without CO2 in the trails. Each cartridge is 25-grams and is threaded for easy use with a CO2 inflator head. Features Five pack 25-gram, threaded CO2 cartridges suitable for high-volume MTB and fat bike tires | Lezyne | 25Gram Co2 Cartridges - 5 Pack Silver