[Easy to Use] We have made transmitter and receiver working together and test it before ship it,when you don't need to do anything ,just install it. [Widely Use] This remote switch used in industrial control and security fields, such as light, motor, remote controller, wireless security alarm, ,lifting equipment, electric doors, wireless door alarm,security industry machine , wireless controller, and other fields. [Signal] Wireless RF signal can pass through walls, floors, doors or . You can use two or more units in the same place. You can turn on/off the receiver with transmitter from any place within a reliable distance(Max range is up to 164ft/50m with no obstacle). [Learning code] the Learning code has high-level security for its low repetitive rate and re-learn mode, it can delete the old code and re-learn a new code,when a remote control get lost,So you could always control of it. Buttons:2 Buttons Remote Distance:20-50M Working frequency:433mhz Max load current:30A Encode:Fixed code/EV1527 code Colour:Black Material:Plastic Package Contents: 1 * Wireless Control Switch 4 * Remote Control Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.