It comes in three different diameters, to fit almost any shotgun worthy of the name. It's a handy way to hang a laser, flashlight, and ??? on your "social shotgun". $55 at brownells.com
mmmmmmmmm.... 3-rail Picatinny accessory mount ....
mrsnad's gripin' that she's gotta buy me a new shotgun tuh hang this thing on...
I did want to comment on this.... I just have a field gun I can't justify mounting anything to, but the idea of a flashlight just sounds really cool.