Features: 6-position Mil-spec Diameter Receiver Extension Tube for AR15 Rifles Extension Tube CNC Machined from 6061-T6 Aircraft Grade Aluminum with Precisely Rolled Threads for Durable Thread Engagement with Lower Receiver Underwent the Tightest Tolerance Controls for a Secure Fit and Function with Various Collapsible Stocks Finished in a Matte Black, Matte Red and Matte Blue Type III Class II Hard Coat Anodize Proudly Designed and Made in USASpecifications: Material: Aluminum Height: 1.45" Length : 7.25" Weight: 4.0oz Color: Black Anodize, Red Anodize, Blue Anodize