This Harmony ZB, padlocking kit for emergency stop function is yellow. It is compatible with Harmony XB4 and XB5 mushroom head push buttons. This padlocking kit is designed as an accessory to be used with push button to provides a secure manner for authorized staff to operate emergency stop mode when required. It is easily installed and attached to Harmony XB4 and XB5 mushroom head push buttons units. It secures machine and system operation with padlock, only available to authorized operators.