BA--Trophy Ridge provides a light (PSE) and a plate, that bolts directly to the top hex bolt of your sight ring.
Here's a link to see what it looks like.
http://www.trophyridge.com/catalog/0...ccessories.htm

However, "I" have had problems with the PSE light and have since 're-threaded' the plate to fit the Copper John Afterburner light.
IMO--this combination is much better and works fine!!!