Add this if you want the ability to escape out of the trailer from the inside through a 24" x 36" galvanized metal escape hatch in the roof, mounted close to the side wall. NOTICE: You are required to also purchase the full walk-on roof for your size trailer. You can also purchase an inside ladder to be attached to the inside wall to access the escape hatch from inside, or you can supply your own after-market ladder. Exterior roof access ladder is also available.