Description: ASG STI Duty One Blowback Airgun (.177 Cal) This Blowback version DUTY ONE is fully licensed by the famous high-end small arms manufacturer STI® International, based in Texas, USA. The 4.5mm (.177) steel BB’s are stored in the drop-out magazine and powered by a 12g CO2 cartridge which is cleverly kept away in the pistol grip thanks to the easyload system. The airgun is semi automatic and based on the classic model 1911 but STI® has upgraded and changed the design and many of the functions. The frame has an integrated front weaver rail for mounting light and laser. The grip is marked with an STI® logo and the high rise beaver-tail grip, secures a perfect hold on the pistol. Furthermore the pistol has unique serial number. The metal slide has beautiful authentic STI® markings. Blowback is a term used when the slide cycles back and forth when a shot is fired. This gives a more realistic feeling and a sense of recoil. Features. Barrel threaded for silencer. Blowback. Accessory rail. Metal slide.