This is a 10x3.85 Slo-Flyer "tractor" (not a "pusher") airplane propeller. This prop produces a lot of torque without a lot of speed.
Computer-optimized design gives these props a thinner profile and more "bite" with less noise. Lightweight molded nylon construction reduces rotating mass for higher output and longer life. Reinforcing carbon fibers help maintain true, constant pitch at any rpm.
Slo-Flyer propellers work well with electric powered Park Flyer-type aircraft.