This is the APC 14x4.7 Slow Flyer Propeller. FEATURES: Long fiber composite construction INCLUDES: APC 14x4.7 Slow Flyer Propeller with two Hub Inserts REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. SPECS: Hub Diameter: 0.50" Hub Thickness: 0.30" Shaft Diameter: 1/4" Propeller Weight: 0.88oz. (24.9g) COMMENTS: Not for use with gasoline engines jxs 04/13/12 ir/jxs