Guntec USA's AR 9mm Multi Caliber Collapsible Stocks feature a heavy duty design and are constructed of high density polymer with multiple cutouts to reduce weight. These stocks feature a neoprene rubber buttpad and also accepts a QD sling swivel on the left or right side. Its multi caliber version is 9mm and includes the buttstock, buffer tube, end plate, castle nut, buffer, and chrome spring. Weighing only 9.4 ounces, these stocks give the shooter a lightweight option for their AR build. These Guntec USA AR 9mm Multi Caliber Stocks come complete with buffer tube, end plate, castle nut, 9mm buffer, and chrome spring. Specifications for Guntec USA AR 9mm Multi Caliber Collapsible Stock: Manufacturer: Guntec USA Color: Black Gun Model: AR-9 Stock/Brace Material: Polymer, Aluminum Gun Type: Rifle Weight: 25 oz Length: 8.75 in Hand: Right Buffer Tube Size: Mil-Spec Fabric/Material: High Density PolymerStock, T6 Aluminum Tube Features of Guntec USA AR 9mm Multi Caliber Collapsible Stock New Heavy Duty Design High Density Polymer Multiple Cutouts To Reduce Weight 9mm Caliber Version Neoprene Rubber Buttpad Included Accepts QD Sling Swivel On Left Or Right Side QD Swivel Included Matte Black Finish Complete With Buffer Tube, End Plate, Castle Nut, 9mm Buffer, & Chrome Recoil Spring Weight Of Stock Shell: 9.4 oz Total Weight Of Stock Kit: 25 oz Package Contents: Guntec USA AR 9mm Multi Caliber Collapsible Stock What firearm models does the manufacturer say Guntec USA AR 9mm Multi Caliber Collapsible Stock is compatible with? The manufacturer says that Guntec USA AR 9mm Multi Caliber Collapsible Stock is compatible with AR-9