The OTB Flash hider works the same as the 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 1/2x28 threads that is .75 or less OD and a minimum of 2.05 of exposed barrel MEASURED FROM THE SHOULDER. RSR -