In AUS it is illegal to side mount your number plate down on the axle as part of the ADR rules you need to be able to see the number plate from both sides of the tyre when standing behind the bike at a 45 degree angle. With this stainless number plate/brake light mount that is possible! And the best part it keeps your rear fender looking neat! 
Plates are drawn up and laser cut so that you can only see a minimal amount of plate under the brake light and above the number plate!
We fit these to all our builds!