Obsidian Arms 3 Gun Thunder Brake Compensator .223/5.56 Stainless Steel. Two chambers vector gasses to the sides to reduce recoil while top ports vector gasses up to eliminate muzzle rise. With this design it will keep your rifle shooting flat for fast follow up shots. Specifications for Obsidian Arms 3 Gun Thunder Brake Compensator: Manufacturer: Obsidian Arms Projectile Caliber: .223 Caliber Threads per Inch: 1/2x28 Gun Make: AR Platform Gun Model: AR-15 Model Generation: 1 Inner Diameter: 0.263 in Outer Diameter: 1 in Length: 2.31 in Weight: 4.4 oz Country of Origin: USA Features of Obsidian Arms 3 Gun Thunder Brake Compensator 3-Gun Competition Reg Compliant: 1-Inch Diameter Less than 3-Inches Long Crush washer shroud to hide crush washer for a more seamless transition Caliber: .223 / 5.56mm Fits 1/2 - 28 TPI Crush Washer Included Package Contents: Obsidian Arms 3 Gun Thunder Brake Compensator What firearm models does the manufacturer say Obsidian Arms 3 Gun Thunder Brake Compensator is compatible with? The manufacturer says that Obsidian Arms 3 Gun Thunder Brake Compensator is compatible with AR-15Obsidian Arms OA-MD-223TB3G-SS-A: 3 Gun Thunder Brake Compensator .223/5.56 Stainless Steel