Product Description Product Info for Alpha Tactical AR-10 Chrome Car Stock Spring, .308 Cal CAR/M4 Size For AR-10 .308 Cal Chrome/Teflon Coated Smoother Cycling And Alot More Quiet Fits Mil-spec/Commercial Buffer Tubes Specifications for Alpha Tactical AR-10 Chrome Car Stock Spring, .308 Cal: Color: Silver Fabric/Material: Chrome Gun Model: AR-10 Package Contents: Alpha Tactial AR-10 Chrome Car Stock Spring, .308 Cal