American National Firearms stainless steel dual-spring recoil guide rod system for Generation 4 Glock model 19 (G19.) This is for a Generation 4 Glock 19 only. It will not fit Generation 1, 2 or 3 models. Please do not try to make it fit other generations, it will not fit, and you can not make it fit. It fits the Generation 4 Glock model 19 only. Lifetime warranty.