CNC 3819 Magnalium 7075 propeller. 1.9" Pitch Ratio. Higher pitch than the cnc-3814250. Designed to be used on 4mm prop shafts. 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 4mm Smooth Bore Propeller Shafts.