Machined MIL-SPEC Aluminum Receiver Extension Tube accepts All M4-style MIL-SPEC Adjustable Carbine Buttstocks and Most Commercials.

Advantages:

• Six Precision-Machined Notches On the Underside Provide Plenty of Options for Setting Length-Of-Pull.
• Perfect for a Custom Build, Installing a MIL-SPEC or Commercial Stock on a Civilian Carbine, or Updating a Fixed-Stock Rifle With an Adjustable M4 Stock.
• Machined From a Lightweight Aluminum Extrusion Then Hard Coat Anodized, and Dry Film Lube-Coated Inside for Smooth Movement of the Buffer and Buffer Spring.
• Requires Carbine Recoil Spring and Buffer, Lock Ring, And Receiver Plate, All Available Separately.