Check the listing for details. APC Electric RC Remote Control Airplane Electric Prop Propeller 7 x 4E 7x4E 7x4. Color: Gray, Condition: New. Listed at 6.95 USD. This is the APC 7x4E Thin Electric Propeller. APC propellers are manufactured using a pultrusion process which allows for a higher fiber (60%) to resin (nylon binder) density. This provides substantially higher strength and stiffness than with glass filled nylon. The additional stiffness is beneficial to control of vibration resonance response. The higher strength allows the use of thinner cross-sections, beneficial to weight and aerodynamic efficiency.FeaturesComputer-optimized design gives these props a thinner profile and more "bite" with less noiseLightweight molded nylon construction reduces rotating mass for higher output and longer lifeReinforcing fibers help maintain true, constant pitch at any RPMThin Electric propellers work well with Electric powered Park Flyer-type aircraftSpecifications:Length: 7"Pitch: 4"