1 mm "fine thread". Old, larger diameter knob for the Faema Express, Special and No Stop models. Also fits the Victoria Arduino Athena Leva model.

1 mm thread pitch means that these have threads on the inside that measure 1 millimeter from thread peak to thread peak, referred to as "fine" thread. These work with any valve that uses the valve fitting.

These look very similar to the La Marzocco knob, but the Marzocco use a 2 mm thread version.