XLAB CO2 Holder Pair your original CO2 Holder with a second one and carry up to 4 CO2 cartridges. The XLAB Multi-Strike C02 Holder is actually the lower part of the Multi-Strike Repair Holder. Used by itself, it easily mounts to the XLAB Delta single-bottle systems, Carbon Wings and Super Wings to securely hold two (2) additional C02 cartridges and a speed chuck or inflator head. Carbon Wings and Super Wings to securely hold two (2) additional C02 cartridges and a speed chuck or inflator head. Organize your race essentials with the Multi-Strike C02 Holder from XLAB. Includes one (1) C02 Holder only. XLAB Multi-Strike Repair Holder, rear carrier, bottle cages, strap, tube and inflation accessories sold separately.