Triangle profile AR15 Handguard for Mid-length gas system AR15s. Top Picatinny rail is at AR15 receiver heights and M-LOK slots are at the 10, 2, and 6 o'clock positions of the handguard. Many shooters finds the wider and flat bottom triangle profile handguards more comfortable to shoot. Easy Drop-In install, no special gunsmithing involved, fit into Delta Ring and front Handguard Cap. Remove factory handguard, drop in the M-LOK handguards and use supplied four screws to secure M-LOK handguard in place. US Patent Pending