Arisaka Defense Finger Stop, Anodized Finish, Black, Fits Picatinny FS-P The Arisaka Finger Stop was developed as a low profile" minimal control accessory. This version is for 1913 Picatinny rails. The Finger Stop has a slim profile which is ergonomically designed to be located between your index and middle fingers. This typically places it further forward on the handguard" which means it doesn't get in the way when transitioning to kneeling or prone shooting positions" where most people move their support hand towards the rear. The wider profile also functions equally well as a rear hand stop" for those who prefer it in this location. Additionally" the Finger Stop functions well as a forward limit to prevent your fingers from slipping off shorter handguards onto a hot barrel or suppressor" and as a barricade rest. The Finger Stop is secured to the rail by two nylon tipped set screws (torque to 15 inch lbs). Due to the low profile design" the Finger Stop must be installed by sliding it onto the 1913 Picatinny rail. The fit is very precise to the 1913 Picatinny specification" so out-of-spec or damaged rails may result in difficulties during installation.