The SI JCOMP Gen2 is the classic Type 89 compensator re-engineered and updated for the 21st century. Due to end user feedback, the favorite features of the original are retained, but the J Comp now features increased muzzle rise compensation, and is available in 7.62x39mm and .308/7.62x51mm in addition to 5.56x45/.223. Now also compatible with Oppressor and FerFrans concussion reduction devices.The J-COMP concept comes from the Type 89 Japanese assault rifle used by the Japan Self-Defense Forces, the Japan Coast Guard's Special Security Team units, and the Special Assault Team.Product Spec:- Length: 2.55"- Weight: 3.6 OZ- Diameter (OD): 0.87"- Diameter (ID): 0.26"- Thread Pitch: 1/2x28- Caliber: .223/5.56Package includes:- 1x JCOMP 2.0- 1x Crush WasherFeatures:- 2 chamber design greatly increases recoil management- Hybrid muzzle brake/compensator- Pre-drilled for pinning and welding- 1/2"x28 thread pitch- for .223/5.56mm