You did not say if it is for front or rear.

On the front, I wrapped some rubber strip cut from an inner tube around the horizontal bar on the rack so that I could us a handlebar mounted light on it. I know this description is not clear, but the picture makes it clear. The light is not on the bike in the photo, but the light bracket is shown on the rack.



For rear I use a vintage Vista light but they are no longer made so I am not describing the bracket, as each light uses different mounting.