Gas airsoft pistols are powered by green gas most often. They can also be powered by propane in some instances, if you use the proper adapter and lube. Some of them have a blowback function, meaning they have a moveable slide that slides back with every shot. This adds to the realism and recoil, but takes more green gas to operate than non-blowback models.
Elite Force Glock G18C Gen 3 Semi / Full Auto Airsoft Pistol Gas Blow Back 6mm
Regular price $199.95
Lancer Tactical Knightshade Hi-Capa Gas Blowback Airsoft Pistol w/ Red Dot Mount - Black & Gold
Regular price $189.49
EMG Custom TTI JW2 Polymer Combat Master Slide + Ultimate GBB Frame Custom Gas Blowback Airsoft Pistol
Regular price $189.95