The assembly is screwed together, like in the older watertight hatch types, but the lid/frame connection is designed in a more modern way, ensuring a resistance of 2 bar. The split seating area of the frame ensures a high strength of the joint, as well as a high resistance to pressure both from above and below.

Round hatches DN600 and DN800 and square hatches 600×600, 600×900 and 900×900 mm.