This is the 20.5x14 Thin Electric Propeller from APC. FEATURES: Injection molded from long fiber composite material which is stiffer and stronger than glass filled nylon INCLUDES: 20.5x14 Thin Electric Propeller with 0.128" (3.2mm), 0.158" (4mm), 0.197" (5mm), 0.237" (6mm), 0.313" (7.9mm) SPECS: Length: 20.5" Pitch: 14" COMMENTS: For use with electric motors, not for use with gasoline or glow engines. jxs 08/29/11 ir/jxs