Black O-ring for Allen access hatches . This seal is designed for 241mm access hatches. The hatch plate is fixed to the boat hull, and the A.638 O-ring is placed around the plate, under the lip . The hatch cover is then screwed firmly onto the seal, ensuring a watertight seal along the entire outer diameter of the hatch.
For hatch model A.637 (or AA637). Original part, compatible with HOLT-Nautos hatches.