The RRD-2C is a shortened version of JMac's 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. Can be permanently attached to a 14.5" barrel to achieve 16" OAL. Product Specs: 5/8-24 Threads .45 Cal compatible (0.50" Diameter bore) KeyMo & KeyMicro Suppressor compatible 2.23" Long Added length: 1.53" 17-4ph Stainless Steel Black Nitride Not intended or recommend for barrels shorter than 10.5" when using rifle calibers When testing these devices wi Mfg: Jmac Customs