Sure Cycle - Stainless Steel High Performance Action Cycling System  for Benelli SBE and M1 super 90 with 21mm receiver threads.   The part is new in the box and unused although I've had it a few years.  The part is missing a washer and bolt which would be easy to find. From what I can tell, it usually retails somewhere between $150-170.  I am only asking $75 since I need to get rid of it and it is missing a washer and bolt.