Schneider Electric Harmony XB4 Push Button Switch, Metal, 40 mm Mushroom, Spring Return, 1NO, 22 Mount, Unmarked, XB4BC21, Black

Amazon

Complete push-button with chromium plated metal bezel Spring return operator Screw clamp terminal connections 1 NO contact configuration IP69, IP67, IP69K, IP66, to EC60536; IK06 IEC 50102 degree of protection

Radwell UK

PUSHBUTTON, 40 MM MUSHROOM HEAD, 1 NORMALLY CLOSED, SLOW BREAK, SPRING RETURN, 22.5 MM MOUNTING DIAMETER, CHROMIUM PLATED METAL BEZEL, IP66/69/69K