Angstadt Arms 9mm Buffer Kit, 5.4oz 9mm AR-15 Carbine Buffer Assembly, Carbine Buffer Spring, 9mm Buffer Spacer, Compatible with Both Glock and Colt Style Magazines, Anodized Black Finish AA09BUFKIT The Angstadt Arms 9mm buffer assembly kit is compatible with both GLOCK and Colt style 9mm AR-15's. Weighing 5.4oz" this buffer is tough enough to withstand the abuse of blowback 9mm firearms and features a dedicated buffer spacer to limit overtravel of your 9mm bolt carrier. Includes 9mm buffer" spacer and carbine buffer spring.