The original was on a short shaft and had no blades, just a flap. It was only able to mix about half a gallon. But with this new four-blade propeller it can mix two gallons with no problems! It is very difficult to buy a propeller because this mixer rotates counter-clockwise and it has a 6mm (rather than 1/4 inch) shaft. And propellers cost hundreds of dollars. But you can design and print one on a home 3D printer with no problem.