Bought on ebay from gbmotorcycleproducts2016(3. The tool appears to be well made. It shipped from UK, and arrived a few days prior to the estimated arrival date. Paid $46 including shipping, which isn't cheap but also won't break the bank. Arriving it had a very slight amount of rust in places, a light coating of oil appears to have remedied this minor issue. I used it today and it worked perfectly, very precise fitting.
An alternative was to buy a wrench. But the wrenches are comparably priced, and it's much easier to torque to spec with a socket. I think this socket will fit many bikes, although it's not clear exactly which. That's another advantage wrenches have, is most appear to be the adjustable type and may be more flexible in their application.