TIRCP - Thumb index recoil control pad. Fits on Picatinny rail. This is the "mini" version is designed to take up a small footprint for when there is limited space available on the handguard. 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. This mini version of the TIRCP occupies exactly 3 Picatinny rail elevated parts and the 2 gaps in between them, unlike 5 and 3 for the other two versions.