DO NOT ORDER THIS PART UNLESS YOU ALREADY HAVE ONE OF OUR FRAME MOUNTED LOWERS. The Underworld Arms Cerberus Upper is intended for customers who already own one of our frame mounted compensators and want to swap to this new style upper. The Cerberuses uses concave gas diverters at the front wall of the expansion chamber to route gas into the two upward angled side ports and the top port. By using this concave diverter the gas retains more of its energy as it is redirected and more gas is trapped and redirected into the ports. The side ports are angled up at 68 degrees which creates a 44 degree arc of gas venting.  The result of these design elements is an increase in recoil reduction and muzzle flip for an even softer shooting experience than our cyclops compensator.  On most builds this compensator will not require recoil spring tuning.    Specifications Material: 7075-T6  Weight: .7oz Length Overall: .825"