aluminum roof hatch designed to provide convenient, economical access to the roof of a building. Each unit comes with an insulated, self-flashing, 12″high curb and a staple for a padlock on the inside and outside. Each unit is supplied with lift assisting mechanisms and an automatic hold open arm. 1 latch. Mill finish. 56″w x 56″h outside flange dimensions. 48″w x 12″d x 48″h return flange dimensions.