Competition 2 M Recoil Control Thumb Rest for Glock Pistol 1. US Patent D472,599. Reduces muzzle jump by 70% (shooting weak hand only) 2. Fits Gen 1, 2 and 3 Glocks, does not fit Gen 4. Beaver tail length: Competition - 9mm (0.35") 3. Increases magazine well opening by 37%. Wings can be modified with a file to fit different hand size. 4. Avoids slide cut on web of shooting hand, increase shooting speed and accuracy 5. Youtube installation instruction: https://www.youtube.com/watch?v=8SkSyF_hefY