I had 2 remote controls, after having lost one I decided to order it to replace. I reprogrammed the 2 codes of openings 2 gates (2 channels) by reproducing the pattern of the first remote control switches. Nothing simpler, it opens by sliding the small plastic compartment in the front. There, you can access the small numbered switches. Just put each switch ON or OFF according to another remote control and voila everything works.
Super fast delivery (next to the letter in the box). Included programming instructions. Battery included. Warranty 3 months.