Lang Range 2000m Wireless Remote Control Switch Module dc 12V 1 Channel Access Control Remote Control Switch Farm Agriculture Switch Relay Output Water Pump Motor Lighting

I purchased this control on April 13, 2020. I am using it as a remote control for a gate that is about 3/4 mile away. It had been working fine for 6 months and it recently failed. I bought another identical unit from Amazon on November 14, 2020 as a replacement. I assumed that the receiver at the gate had failed. When I got the new system I paired the new transmitter with the new receiver. I then tried to pair the old transmitter with the new receiver and it would not pair. I then thought that maybe the transmitter was the problem all along so I tried pairing the new transmitter with the old receiver and it paired fine. Since it was now obvious that it was the transmitter that failed I wanted to buy a spare transmitter. The gate to my horse ranch is 3/4 mile from the house and not visible from the house. Being able to open and close the gate without driving all the way down the mountain is a HUGE deal. I contacted the seller and explained the problem. I asked about buying a transmitter. Instead the seller offered to send me a free tranmitter. WOW!! What incredible service. They shipped the unit right away and I got it less thanb a week later.