This quality Receiver Extension (Buffer Tube) is machined to military specifications (1.14″ Diameter – which is slightly smaller in diameter than the commercial spec tube) from a 7075T6 aircraft aluminum extrusion to accept the 6-position adjustable mil spec telestock and other mil spec bored stocks. Precision notches on the under side offer 6 positions for setting length of pull. Finish is hardcoat anodize -Mil-A-8625F, Type III, Class 2. Note that if you use a commercial spec buttstock on this mil spec tube, it will rattle. Made in the USA.