I purchased one at Oshkosh from Wag Aero. In fact it was the owner of the company that sold it to me. They make the bars themselves. It is heavily constructed, nicely painted, uses a strong spring to pull the sides together and a bolted lever to open it up. I cannot image why you would need it to lock because the design is such that it will stay tight on the fork. The two sides are welded to the center section and the welds are more than adequate. It uses a pin to allow the handle to expand out so it takes up a smaller space yet gives you plenty of length for towing without banging your face on the spinner when using it.
This said, it has yet to be test flown. After I put the bolts that it attaches to on my fork this weekend I can give you a better review on its actual performance.
This all said, we use similar tow bars for all my flying club and CAP aircraft and never have had a problem. That is on over 18 different and much heavier aircraft. Because of this point alone I could not justify the much higher cost of the Bogie Bar. It's not something my life depends on and I'm sure my wheel fairing will be just fine.
Mike R.