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 11x5 props have a 6mm hole drilled in the front side of the hub, and an 8mm hole on the back side of the hub to accept a prop shaft adapter ring. Also included with the prop is a set of 8mm OD adapter rings that step down the center hole of the prop to allow it fit on 2mm, 3mm, 4mm, or 5mm motor shafts. If you have a larger threaded shaft on your prop adapter, the center hole can be reamed out to a larger size as needed.