19 x 13.5 x 1.5 mm - suitable for most 1/4" applications.

Specifically, when used on a La Marzocco, these are found with the 1/4" group head, drain cup and boiler fittings, as well as pretty much all of the other 1/4" fittings on Marzocco or any other equipment. Best fit (metal gasket) for 1/4" fittings we've found.