SilencerCo handgun suppressors have pistons that are easily changed for different host weapons or sub-calibers. These pistons are easily interchangeable for compatibility with all relevant host guns and can be changed out to be compatible with sub-caliber host guns, which means you can shoot smaller caliber rounds through the same suppressor, making it a multi-caliber silencer. This coupler ring holds the piston in place so that the suppressor is in perfect alignment.