Rad Power used to let the users adjust the speed limit.
From what's been reported here on EBR from other Rad owners, apparently Rad decided to lock the user option to raise the speed limit as of 2021.
This is why you will see older Rad Power LCD display going for high prices on eBay (as previously discussed here on EBR) because Rad will no longer allow customers to adjust the speed limit.
The other option would be Bolton or Electro Bike World.
These aftermarket controllers / displays are better anyways.
***This does NOT include a tail light/brake light as this is the tail light version to work with an already existing tail light. Most Rad bikes have that already.*** 35a controller and new color LCD8H. Plug and play for 2016-2018 Radrover bikes. Please note that the controller has a tail light...