https://rwo-marine.com/store/deck-hardware/inspection-covers/r4045-o-ring-seal-for-r4040-pk-size-2/
R4045 - O Ring Seal For R4040 (Pk Size: 2) - RWO Marine
Oct 28, 2020 - Spare "O" ring seal for 100mm inspection covers (pack of 2) use with R4040, R4042, R4045 and R4047
o ringseal