This is a 5.25x4.75E 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 Two adapter rings adapt to different motor shafts INCLUDES: One composite propeller Two composite adapter rings One instruction sheet REQUIRES: ALL props require balancing (use TOPQ5700) May need prop reamer, use GPMQ5005 (SAE) or GPMQ5007 (Metric) SPECS: Diameter: 5.25" Pitch: 4.75 Hub inner diameter: 0.25" jxs 2/23/05 ir/jxs