If it is new, a wrench should be included. If it is a 12 ga then a quarter should suffice. I have several wrenches ranging from several "universal" wrenches that came with aftermarket tubes which are merely a half moon piece of metal with a handle to the notched pieces of metal sent with the gun to socket looking things with knobs on the side and a T-handle. All worked as well as the other though I replace the flush mount chokes with extended for ease of changing. I just hand tighten them and check periodically.
