I purchased a set of inexpensive metric 3/8" drive hex sockets from Harbor Freight. The set had the correct size for the engine mounting hardware ... which, if memory serves me correctly, was 6 mm (but don't hold me to that).
I also purchased the extended ball tip version when they were on sale for around $9.
Happy flying .... after spring thaw LOL
RV-12 Wings, Empennage, Fuselage, Finishing, Avionics and Powerplant kits all completed
Dues paid until September 2019