Aim Sport's AR/M4 Combo kit is ideal for upgrading your flat top and optics ready AR-15 carbines. Included in the kit is a diopter folding rear sight, gas block height front sight, vertical front grip, and a 4694 STANAG carbine length quad rail. The quad rail is constructed of black anodized aircraft grade aluminum, accepts all standard Weaver / Picatinny 1913 accessories, and is compatible with most carbine length direct impingement gas systems. Its vertical grip features a black polymer finish and is compatible with Weaver / Picatinny 1913 & Stanag 4694 Rails. The sights are constructed of black anodized aircraft grade aluminum, feature a ball bearing pivot detent, are quick detachable, have a Flip-up posi-lock design to guarantee zero, and automatically lock into position when raised.