Full length rod replaces the short, factory spring plug and guide rod for increased spring support, better reliability and smoother functioning. Two-piece, hex head guide rod and one-piece recoil spring are fast and easy to install. Installation requires only slight modification to slide. Mfg: Wilson Combat SPECS: Machined stainless steel guide rod/head and plug. Heavy duty recoil spring. Officers ACP Rod (Off): .326" (8.2mm) diameter.