This is a quality 0.050" allen-key style hex wrench, ideal for tightening hex socket set screws like the ones used in our RW2 wheels.
After being frustrated after stripping too many hex wrenches while tightening RW2 wheels onto motor shafts, we decided to get some good hex wrenches. These Bondhus brand hex wrenches have been doing a great job for us. They're an ideal companion for any RW2 users!