Pentair - 27001-0061S Cord-Ring for Sta-Rite PLM Filter Systems

Much more expensive in local pool store. Perfect fit. Includes small amount silicone lube (do not use any petroleum lube).
Caution - this O ring expands with time and/or reusing the same O ring more than once result: - can not reinstall because O ring buldges out and can not close filter. Always use a new O ring when disassembling the filter for cleaning.

This was a very difficult item to find. I received it within 3 days. Very halppy with this order and product.