Available in 18Airsoft right now are the Army Force CO2 Charger that comes with a built pressure gauge so you can have an easy readout when doing a refill. Made of stainless steel the cylinder can hold one 12g CO2 cartridge and has been designed to prevent leaks for a long periods of time. Available in Black-Blue or Green-Blue colours.
Svoboda Airsoft of Taiwan announced that their 20mm CO2 chargers are now available... "The 20mm ammo now is ready for sale. There are three configurations for your preferences: M53 Armor Piercing Incendiary (API), M56A3 High Explosive Incendiary (HEI), and MK149 Armor Piercing Discarding Sabot (APDS). You can put a 12g Co2 bottle inside as a Co2 Charger, and an adornment when not in use. Please contact your local dealer for this interesting tool."