The 71L-F is rail mounted with a quick deploy latch and adjustable for elevation. Made from durable, metal-reinforced polymer and are a good option when seeking a quality sight. Measures: .600a ^2 when in the folded position, from the top of the receiver. Length: 2 1/4a ^2. Designed to fit all universal dovetail rails, and free float handguards parallel to receiver. Do not mount to Dovetail Gas Blocks. ONLY THE A.R.M.S. #71 POLYMER SIGHTS HAVE STEEL APERTURES THAT ARE NOT AFFECTED BY HEAT! 100% MADE IN THE USA.