A SLIM & COMPACT version of JMac's ever so popular RRD-4C. The RRD-2C is a shortened version of their popular RRD-4C muzzle brake. The RRD-2C was created by removing the 2 smallest ports from the RRD-4C, creating a more compact package while still maintaining the ability to mitigate recoil. Product Specs: Weight:1.23 Ounces 14-1LH Threads 10mm Bore 17-4ph Stainless Steel Black Nitride Not intended or recommended for barrels shorter than 10.5" When testing these devices, JMac found that high rates of fire such as full auto or "mag dumps" could cause damage to the device due to the excess heat, pressure, and gasses Mfg: Jmac Customs