Hi Marc
Do you live in, or near to, a marine environment - if so, have a look at the attached file.
Cheers
Dennis
EPDM washers link:
https://www.bunnings.com.au/zenith-2...-pack_p2409517
EPDM stands for Ethylene Propylene Diene Monomer, a synthetic rubber used in a range of applications. EPDM is used most commonly used in the automotive and construction industries for various seals due to its excellent resistance to environmental factors such as Ozone, UV and general weathering.