, I'm rather skeptical about such items. It was clearly used and salvaged by another switch that may have been bricked up or beyond repair, but I figured out what was going on. Now: About a month ago I spilled a glass of water on my coffee table and thought my switch was broken. Instead of letting the switch dry before turning it on, I checked to make sure it was working properly and everything was fine. I'm not sure what happened, but the next day there was a problem with the joycon docking properly. It failed to detect the correct joystick in handheld mode and could only be used wirelessly. The strange thing is that the joycon was still charging. This ruined the Switch for me since I play handheld most of the time. Before I sent the Joycon to Nintendo for a lot of money, I decided to try everything I could find on the internet. Nothing worked. Most people who have had this issue seemed to be resolved by power cycling the controller, refreshing, or permanently unplugging and plugging the controller back in. Mine was clearly water damaged so none of that worked. I approached this product at Revain to try a homemade solution not knowing if it would work. Just installed the new right rail and the switch will recognize the joycon! Thanks very much!