CNC Magnalium 7075 metal propeller. 1.9" Pitch Ratio. If you have used a similarly sized 1.4-pitch-ratio prop, this will be the next prop to test.Size options from 40mm to 48mm diameter; see picture 3 for specs Prop RecommendationsProBoat Sonic 24, cnc-4019250: Upgrade will require pn# ose-cable-sonic-24.ProBoat Blackjack 24 v2, cnc-4519250.Traxxas Spartan, cnc-4519250. Machine-cut to high tolerances, this prop is 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 viewed from the back of the boat. Fits 3/16"(.187" 4.76mm) Smooth Bore Propeller Shafts.