This Ncstar MARFLF/2 AR 15 Flip-Up Front Sight A2 front sight post assembly is Receiver Height for Hand guard Rails, Monolithic Receivers, and Gas Blocks that are at the SAME Level as the AR-15 Receiver Rails Flat Top. The Flip-Up A2 Front Sight Post folds down out of view of your optics when not in use. The A2 front sight post is fully adjustable for elevation. Aluminum and Steel Construction. Overall Height: 1.8" Extended Up, 1.0” Folded. Limited lifetime warranty.