Used on fire truck's vertical front for mounting warning light or siren. See example in final photo here. This one came from a truck with a horizontal trim strip, which required the bracket to be notched at rear to fit over strip. Mounting surface for this one is 6-1/2" x 9". Your device may or may not match the existing base holes, but can be drilled to accommodate. Some have also been adapted to mount another device on the angled lower portion. Excellent condition. $85 + shipping.