The WHISTLE TIP is a blast mitigation device (BMD) for our Cherry Bomb muzzle brake. It also serves as a Cherry Bomb thread protector. As you've come to expect, the WHISTLE TIP features a taper mount for proper alignment to the Cherry Bombs and installs with any off the shelf 1-inch wrench. "It's that woo woo! You know what I'm sayin'?" SPECS: WEIGHT: 2.7 oz. OVERALL LENGTH: 1.85" OUTSIDE DIAMETER: 1.16" INSTALLATION: RIGHTY TIGHTY TORQUE TO 10-15 FT-LBS