Specifications: For All AR15/M4 Carbines Stainless steel flate wire 1.8oz Approx 37 Colis 15.5 Inches 17-7SS with Sandstrom 28A coating flat wire buffer spring. Increased performance and reliability. Smoother shooting and longer life cycle. A reference for the Sandstrom 28A coatinga | Sandstrom 28A Coating provides excellent corrosion resistance and is used by the U.S. Department of Defense 100% MADE IN USA