Century now has the perfect solution, with new technology, to construct high quality, multi-laminated, wood rotor blades. Only Aerotech blades fit both 3mm and 4mm blade bolts interchangeably and with new factory techniques, can double the speed to statically and dynamically balance every single blade. You can pick perfectly matched pairs at very affordable prices. Blades are already weighted and balanced. Just....INSTALL & FLY !!