Genuine, Mil-spec, high quality parts for those AR-15/M-16 small parts that wear down, break, or simply get lost. With this Small Parts Kit on hand, you'll always have the parts you need to keep your rifle running smoothly. These high-quality parts are manufactured to precise tolerances to ensure a correct fit with your 5.56 AR-15/M16 rifle. This convenient Small Parts kit contains all the parts needed to keep your 5.56 AR-15/M-16 rifle like new.Parts include: Firing pin retaining pin Ejector Ejector spring Ejector pin Extractor spring with insert Extractor axle Gas rings (3) "O" ring (donut)