Shaver SM-265-D cylinder cup seal. This is the seal located at the top of the cylinder cup on a HD-8 post driver. Please refer to your parts manual to verify fit. Note- this seal doesn’t fit some of the early model Shaver 8 inch drivers. (Older models have a urethane seal that is white in color) We do stock this part and it can be bought on our site under the heading “Early model Shaver 8 inch post driver cylinder cup seal”