Siemens Mushroom p/button, momentary contact, green, 40mmProduct Overview Mushroom pushbutton, 22 mm, round, metal, shiny, green, 40 mm, momentary contact type. Part of the SIRIUS ACT series, this mushroom pushbutton features a large handle for comfortable operation with your whole hand. Under the SIRIUS ACT brand name, Siemens offers a unique portfolio of commanding and signaling devices with worldwide product approvals in four modern design series made of robust real metal and high quality plastic.