Schneider Electric push button, Harmony XB4, metal, flush, green, 22mm, spring return, white marked I, 1 NO, compact in terminals

Amazon

Green opaque push button Simple modular design facilitates post installation servicing, modification and adaption of machines by non-specialists

Radwell UK

0.87 INCH MOUNT HOLE, FLUSH, PUSHBUTTON SWITCH ONLY ROUND, GREEN PUSHBUTTON, NONILLUMINATED, MOMENTARY (MO), SHOCK AND VIBRATION RESISTANT