The OTB Muzzle Brake works the same as our standard OTB mount, only with a built in muzzle device – Made from H900 heat treated 17-4 steel this one piece adapter will allow you to mount your OPS 12th model, OCM5 or AEM5 to ANY barrel with 1/2×28 threads that is .75 or less OD and a minimum of 2.05 of exposed barrel MEASURED FROM THE SHOULDER. Pick your flavor of black nitride coated or raw heat treat, slap it on your rifle and go – no custom collars or custom barrel work needed.