Wanna convert your TW become Civilian Spec semi auto only or a precision SPR? FCC produce Anti-Full Auto Selector Rack (Semi auto only). You can simply by replace your original selector rack to disable full auto function immediately. Not necessary to do anything on electronic panel in order to do ONE-SHOT-ONE-KILL! SUS304 stainless steel precision machined & polished by hand, durable ONE-FOR-LIFE, compatible with FCC complete CNC gearboxs, Celcius, OEM & Systema gearbox.