Someone should know? The recover kit from pete will have grommets but was needing a grommet size for buying a grommet tool. On the Krates I pulled apart an original seat and the hole seems to be 7/16" and I think grommet size is based on the size of the hole it fills? Research shows #3 are a 7/16". Also have a 5 speed seat and the inside of the grommet is 1/4" but would have to guess that it may be a 5/16" grommet? I would recover it but nothing is available and is a soft original with only a tiny cut.