Beavertail propellers are designed with a CAD/CAM computer system and are extensively tested to match each engine power characteristics. Other propeller manufacturers simply do not have the computer system and engine detail necessary to design propellers that exactly match engine design. Beavertail believes that when you purchase the finest mud motor available, you deserve the finest propeller. This is the top of the line propeller. It is specifically designed for the combination of high speed and aggressive mud performance. Designed with blades specifically shaped and negatively raked to reduce any chance of weed buildup around the propeller hub. These props are standard on all Beavertail motors. Thread: 3/4 10 Thread