CNC 7512 Magnalium 7075 propeller. Machine cut to high tolerances makes this prop ready to use right out of the box. The Magnalium 7075 alloy makes this material upwards of 30% stronger than standard 7075 aluminum. Left hand rotation. These spin counter clockwise when looking at them from the back of the boat. Fits 1/4" (.250" 6.35mm) Smooth Bore Propeller Shafts.