STABILITY: it is a timer relay module with high precision, stable and reliable performance 2 MODES: support 2 modes, mon mode(once) and cycle mode, and you can simply switch mode by adjusting the jumper USAGE: connect 2 wires of Key if you need module to work recurrently after power on ADJUSTABLE DELAY TIME: there are many voltage and time range for your choice, both on time and off time are adjustable APPLICATION: widely used on timer operating equipment, machine repetitive test circuit, fish tank intermittent pump, etc