7in 9in 10in 12in 15in These sleek, modern designs, are brand new in ohhunt offering such features as a steel barrel nut, and machined anti-rotation tabs. Cut for weight reduction, this system still retains the utmost in robust construction and provides a Picatinny top rail mounting system and plenty of attachment points for all your M-Lok accessories. Compatible with M-Lok accessories Works with low profile gas blocks M-Lok mounting surface for ultimate modularity 1913 rail meticulously engineered to be ultra light