Designs 1221-DOW and 1221-OW are "away from wall" higher performance mixture hearth/smoke damper precisely designed for applications the place the damper can't be mounted throughout the airplane of the wall or floor. They attributes Nailor’s unique inter-locking double skin airfoil blade structure that removes combustible seals and provides flame and smoke seal below https://heavydutystainlesssteelda90122.techionblog.com/37006198/a-review-of-heavy-duty-stainless-steel-damper-manufacturers