CNC 3819 Magnalium 7075 propeller, 1.9" Pitch Ratio. Higher pitch than the cnc-3814250 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 counterclockwise when looking at them from the back of the boat. Fits 3/16"(.187" 4.76mm) Smooth Bore Propeller Shafts.