This lock out is designed to allow your booster to work on a rifle or on a pistol with a fixed barrel. Simply change out the spring in your booster and replace it with the lock out.
NOTE: You must shoot with the lock out a few rounds and then re tighten the booster after the part has settled. This is a very important step that cannot be skipped to avoid damage. SDTA will not be held responsible for this or any other product being used incorrectly.