So...I picked up some Briley chokes for a Benelli M4 that did not happen. I ended up getting the M2 and unfortunately it is a different choke system. Like an idiot I opened up the packages and now they are just sitting there, mocking me. They have not been fired and are brand new save for the missing packages (I tossed them and do not want to dig out the little cards/busted up plastic).
They are the extended type complete with the knurled ends (no wrench necessary). I have the Improved Modified and Improved Cylinder. They are compatible with the "mobile" system which goes with the Benelli M4 and some of the Barettas.
Here is a description from an internet retailer:
Briley Extended(X2) chokes are designed to give the shooter more uniform patterns and ease of identification. The extension allows for a more gradual taper leading to less pellet deformation. It also allows room for a parallel section to be built in which further improves patterns.
I paid $45 each plus tax, but I just found them on the interwebs for $39 each plus shipping. Lets put them at $30 each including shipping (cont US) and paypal fees.