Timer Relay Module One Way Trigger Cycle Timing Delay Switch Circuit Board Accessories.Feature: 1. The signal ground and the system ground are not in common to improve the anti interference ability of the system. 2. Equipped with an industrial grade circuit board, the setting parameters will always be remembered after power failure. 3. Supports micro USB 5.0V power supply, and is very convenient to use and simple to operate. 4. This interface is clear and simple, has powerful functions, easy to