Crosstac Mk109 Muzzle Brake Wrench Delrin Black. Tool fits all models from 223 to 308. Machined from Delrin this tool will not damage the porting of your brakes. Please note: this is more of a removal tool than used to over-torque the brake on. Our brakes hold with very little torque required. Only snug them on with this tool about 1/16 to 1/8 of a turn Specifications for Crosstac Mk109 Muzzle Brake Wrench: Manufacturer: Crosstac Fabric/Material: Delrin Plastic Quantity: 1 Package Contents: Crosstac Mk109 Muzzle Brake Wrench Crosstac 135702: Mk109 Muzzle Brake Wrench Delrin Black