The ENDO Tactical Stock Adapter for Glock (Model and SB braceTSA-G) is a specialized polymer accessory that attaches to the grip cavity offull-sized Gen 1, 2, and 3 Glock pistols to mount AR-15/M4 receiver extensions, braces, or shoulder stocks. ®Compatibility and Design• Supported Firearms: Fits standard full-size frames including Glock 17, 18, 20, 21, 22, 24, 31, 34, 35, and 37 (Gen 1 through Gen 3).• Frame Limits: Not compatible with short-frame (SF) or Gen 4/5 models without modification due to grip cavity design changes.• Attachment: Locks securely into the lanyard/grip cavity slot at the base of the handle without permanent gun disassembly. I have Black or Green. Used each one once. $120 each. Buyer must have a CCW permit and be 21. I will ask to see. If you were responsible enough to get the permit then you should know how these work and what the rules are.