The advanced technology ar-15 commercial buffer tube assembly package fits most ar-15 and ar variants.It features a 6-position 7.8" hard-coat anodized 6061-t6 aluminum buffer tube with a slanted back and commercial thread and tube diameters of 1.17".This assembly also comes with an ar-15 recoil plug buffer spring and a steel castle nut and locking ring.Made in the usa.Note: this model is compatible with ar-10 308 models.Rails: Black AnodizedType: Buffer AssemblyFirearm Type: Commercial Buffer Tube AssemblyMaterial: AluminumFinish: Anodized