This is a 6x4E Thin Composite propeller from Advanced Precision Composites. For use on Electric powered aircraft only (not for glow engines). FEATURES: Gray composite propeller blades that assemble onto a propeller hub. Comes with two adapter rings that adapt to different motor shafts. Comes in a bag attached to a header card. INCLUDES: One composite propeller Two composite adapter rings One instruction sheet REQUIRES: Assembly onto motor or gear drive unit in your Electric plane. Balancing SPECS: Diameter: 6" Pitch: 4 Hub inner diameter: 0.25" COMMENTS: Use Speed 400 Electric motors. baw 11/29/01 ir/kh