Steffen from Rhinomoto and I worked together to come up with a solution for bar end mirror adapters for the RC 390 since I realized there is a great lack of screw-in bar end adapters on the market for our bikes. He was awesome to work with and I recommend you shoot him an email [email protected] if you are interested in getting a pair for your bike. He had me order the 150-0151 kit, then custom made some .250" spacers for me since the spacers that come with that kit are too small and bind the throttle. He may create a ready to go kit in the future, but if you want them now you'll probably have to ask for this custom kit for the RC 390. Mirrors attached are CRG. Here are the results: