AR-15 Hybrid Buffer Tube Package- 6 Position Hard Coat Anodized T6 Aluminum Hybrid Buffer Tube- Hard Coat Anodized T6 Aluminum Buffer- Military Spec Thread Diameter for a Tight Fit on AR-15 Receivers- Large Commercial Spec Tube Diameter to Provide a Tight Fit on After Market Buttstocks- Buffer Spring- Steel Military Grade E-Coating Castle Nut- Steel Military Grade E-Coating Locking Ring