Part Number FE308BAD2. Seiko Case Back Gasket Seal Replaces. I have collected Seiko watches for 50 years. For sale, 1 Gasket Seal Rings (0.7 mm thick). I can check you have the correct part, or give you the correct part number.
Seiko Case Back Gasket Seal FE318BAD2 see list
Seiko Case Back Gasket 1 part FE338BAD4 see list below
Seiko Case Back Gasket FE328BAD2 see list below
Seiko Case Back Gasket FH2980B0A see list below
Seiko Case Back Gasket FE298BAD2 7S26 & 7s36
Seiko Case Back Gasket FH2980B02 see list below