The ERGO 2 Flattop AR15/AR10 Suregrip is a truly ergonomic, shooter focused flat top grip for AR platform rifles and chassis systems. Designed for performance by creating a better interface between the shooter and firearm, the Ergo Grip is still the standard by which positive grip and shooter comfort are measured. The Ergo Grip comes with the patented Gapper(TM) for increased comfort.Features :Designed for both .223 and .308 AR-15 type lower receiversFits modern chassis system stocks commonly made for bolt action rifles and AR15/AR10