This Harmony ZBY marked legend has black background and is marked with “O-I” lettering.It is compatible with Harmony XB4 and XB5 push buttons and pilot lights.This legend provides clear labelling for your push buttons.It is supplied ready engraved with a marking relevant to machine operation and is compatible with any standard 22mm Harmony control and signaling units.It provides clear and resilient symbol marking on the label, with high contrast.