Laser cut out of steel and powder coated Black these brackets are designed to work with the bolt spacing on any of the Motone Round tail lights (Eldorado, Bel Air, Miller, Lecter, Cuda, etc) 

You can use this bracket anywhere on the bike - or it also is designed to slide in between Motone fender light brackets and Motone tail lights in an assembly so you can mount a plate with them, with the down facing lights on the tail light illuminating the plate.