CNC 3414 Magnalium 7075 propeller, 34mm Diameter This propeller fits 4mm smooth shafts that have a drive dog and is held on by a nut. 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.Specs: 34mm diameter 1.4 pitch ratio1.88" (47.75mm) total pitch