These parts are all the 'O' rings and gaskets you need to swap out when they go bad on the hubs. The part number is 29061 and can be aquired at any Warn dealer or Napa Auto Parts store, or so Warn's excellent customer service told me.

I bought one of those with the hubs. It came with a gasket instead of a rubber O-ring seal for the hub body.

It may have been an old version of the kit. Warn told me they used to use a gasket on the body but found that O-ring sealed better.