This is a 2-channel transmitter, it can be installed indoors and outdoors, it is activated after you enter the correct password. 

It's for automatic gate and similar mechanical devices. Launch codes will change every time to ensure the safety of the product. 

Usually, our tubular motor receivers are one set photocell(emitter and receiver) or two same type sets (both contactor or both impulse) connected, but, TM5820 can be connected with 2 sets of different photocells(either contactor or impulse). 

Hiland just do our best job in packing process to make our customers' goods protected. 

Usually, there is more or less interference between 2 sets of photocells when they work. In the past years, Hiland also faced this problem. Now our engineer has improved this and successfully make less interference between photocells. That is, we have enhance the anti-interference function of photocell. When one set of photocells works, another one are not that easily influenced.