You may be able to use a universal option like the K-Source Universal Towing Mirrors # KS3891-2 on your 2021 Nexus Rebel 30R. These fit most mirrors that are 4-1/2" to 11-1/2" tall so you will need to take a quick measurement to make sure they fit your existing mirrors. We don't have any custom options for the mirrors on your International chassis. view full answer...