GemFan produces some of the finest propellers for Multi-Rotor use, and they are available in a variety of colors and materials. All of the different sizes are available in both normal and reverse rotation as needed for use in multi-rotor craft.
Graupner-style design. The 9x5 props have a 6mm hole drilled in the front side of the hub, and an 8mm hole on the back side of the hub. If you have a larger threaded shaft on your prop adapter, the center hole can be reamed out to a larger size as needed.