How to quickly set the time: You can quickly set the time by measuring the voltage (Uc) of the resistor. Take the 5V 15min module as an example. If Uc=2V, then time=2V/5V*15min=6min. This relay module is widely used in timer operation equipment, machine repeat test circuit, fish tank intermittent pump, etc. This 12v timing switch is a timing relay module with high precision, stable and reliable performance. The time range that can be set is very wide, the on time and off time can be adjusted 12v relay timer is very suitable for controlling the reciprocating stroke, or repeated power-on and power-off of equipment and product aging tests Supports 2 modes: mon mode (once) and cycle mode , you can simply switch the mode by adjusting the jumper Quantity: (1-pack) Timer Switch Relay Module, other products not included Size: 70*20mm (for reference only) Color as shown Note, because there may be color and size difference between the light effect photo and the actual product, please allow 1-2 cm error