This is an APC 13x4EP Electric Pusher Propeller. FEATURES: Composite construction, gray in color Thin propeller designed ONLY for Electric use INCLUDES: One APC 13x4EP Electric pusher propeller with one each .128" (3.2mm), .158" (4mm), .197" (5mm) .237" (6mm) and .313" (8mm) locating rings for a more precise fit SPECS: Hole diameter: 1/4" Propeller diameter: 13" Propeller pitch 4 COMMENTS: Do not use with nitro or gasoline powered aircraft. lmm 6.16.11