This is a Luth-AR Buffer Tube Complete Assembly, model BAP-308.
Luth-AR's Fixed Rifle Length Buffer Tube Complete Assembly Kit includes everything for a new .308 AR A2 Rifle build or to convert your current AR Carbine to a A2 Rifle buffer tube recoil system.
Features:
Kit includes a .308 buttstock extension tube standard .308 buttstock buffer spring and a standard buffer body assembly