... head) XB2-BR51 NO yellow diameter 60(head)above emergency stop pushbutton switch are spring retern TypeContact typeColorSlackXB2-BC21 NC ... head)XB2-BC21 NC red diameter 60(head) above emergency stop pushbutton switch are spring turn to release TypeContact ... , illuminated push button, maintained push button, Mushroom push button, emergency stop button, selector switch, key switch, dual push button, ...