YHM makes two front sight flip models. The YHM-9584 (also sold on our site) is taller and is designed for placement on railed gasblocks which sit lower than flattops. The sight designed to sit on the same plane as the flat top rail on the handguard or forearm is this model, the YHM-9627.
A-15/EM-16 & A2 Front Sight, Front Sight Only "The Low-light Advantage". Get an advanced low light sight for less than the cost of most standard BUIS!