This Muzzle Brake kit is designed to replace the existing Flash Hider which comes standard on the RFB Rifle. This Muzzle Brake is designed to lessen the felt recoil of the RFB and the vertical muzzle lift as the rifle is fired. The combination of these two will allow the shooter to re-gain their sight alignment quicker for follow-up shots. - This kit comes with one (1) RFB Muzzle Brake one (1) Lock Nut both machined and heat treated from 4140 steel. - Tools Required for Installation: Two (2) thin wrenches with �� opening.