(3 seconds) on the DPI or specific light button often turns the lighting on/off. Silent Clicks
If you have searched for the term you are likely holding a piece of technical equipment—perhaps a industrial timer, a temperature controller, a battery charger, or a specialized relay—and you need to figure out how to make it work. The ZN-401S model number appears across several electronic components, most commonly in the industrial automation and power management sectors. zn-401s manual