These are replacement insert modules for GlockA(R) pistols to be used in Ergo's MAST(TM) Modular Armorer STand(TM) System. Ergo's MAST(TM) modules for GlockA(R) can be clamped in a bench vise, bolted to the side of a bench, or inserted in the Ergo's MAST(TM) base to support your pistol for display, maintenance, cleaning, or storage. Small Frame Module holds double-stack GlockA(R) pistols chambered in 9mm, .357 SIG & .40 S&W Ergo MAST(TM) modules for GlockA(R) are made of rugged reinforced molded polymer, with two hardened stainless steel pins that lock the insert module into the base. Mfg: Ergo Grips