The MSA logo on the lens should be on the bottom and centered in the face piece opening.
Place the bottom edge of new lens (6) into the groove of lens seal (7).
Carefully work lens seal (7) around the new lens (6) edge.
Attach lower lens ring (4) and upper lens ring (3) to face piece (5) using nuts (2) and retaining screws
Stick a new lens cover (8) over new lens (6).
3-9.2.20 Removing/Installing Spectacle Assembly.
Fold the head harness straps over the front of the face piece.
Squeeze retaining spring (2) together and pull spectacle assembly (3) out of the face piece.