Original seal for HOLT or ALLEN hatches. This seal is suitable for Holt and Allen brand hatches, part numbers HT.537 or A.537, 157mm diameter . This seal is positioned on the outside of the flange or plate fixed to the support. Once screwed in place, the hatch seals properly with the seal on the outside.
For hatch model AHT.537 (or AA.537). Original part, compatible with Allen hatches.