TIRCP - Thumb index recoil control pad. Fits on Picatinny rail. This is the "textured" version which has gripping texture designed into the surface of the material. This texture makes this version not well suited to applying grip tape. Fastening hardware and hex wrench for installation is included. The top of the TIRCP extends 14 mm (9/16") above Picatinny rail, which is about 22 mm (7/8") below typical iron sight height, meaning it is below the center of all typical optic heights. The TIRCP occupies exactly 5 Picatinny rail elevated parts and the 4 gaps in between them.