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