The elastic seal is a metal ring that fits around the piston, the solid section of the seal should face the rear, the toothed edge should face forward. To install the seal on the piston, place the seal over the front of the piston body, teeth facing forward. Starting at the split, push one end of the seal split over one retaining nub on the piston body. Continue working the rest of the seal in a circular direction over the remaining retaining nubs until the seal is retained on the piston. Remember to always squeeze the split of the seal together when installing the piston into the piston housing of the barrel. Failure to do so may bend the seal rendering the shotgun inoperable. When assembling the shotgun never place the piston on the magazine tube and install the barrel, this will cause the seal to deform when the action is closed rendering the shotgun inoperable, always place the piston and seal into the piston housing first.