The Glock 17 Gen 4 CO2 Airsoft Pistol is a CO2 powered handgun is a full blowback 6mm pistol! Fully licensed by UMAREX this GLOCK has all the features of the firearm, but in a 6mm airsoft version. This is the GEN 4 edition of the full frame Glock 17. It uses standard 12-gram CO2 cartridges that insert into the magazine that holds 23 rounds. This GLOCK 17 Gen4 has a fully adjustable airsoft ho-pup system and fits most if not all standard GLOCK 17 holsters, accessories, and gear. Officially Licensed Product of GLOCK.