NcStar Tactical Weaver Rail Adaptor For Glock 17 19 22 23 Pistols MADGLO Accessory Rail will allow you to add accessories to Gen 1 Glock Pistols. Rail Easily Mounts to the Trigger Guard (No Gunsmithing Required). Made of High Quality Aluminum. Fits 9mm & .40 Cal Gen 1 Glock Pistols and Sub Compact?Glock?Pistols without Factory Rails. Weight: 1.4 oz