This is a 13x8E Electric ONLY Composite Propeller from Advanced Precision Composites FEATURES: Gray composite one-piece construction Five adapter rings that adapt to different motor shafts INCLUDES: One composite propeller Five composite adapter rings REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. May need prop reamer, use GPMQ5006 (SAE) or GPMQ5007 (Metric) SPECS: Diameter: 13" Pitch: 8 Hub inner diameter: 0.25" (6.3mm) COMMENTS: For use with Electric motors only. Do not use with nitro or gasoline powered engines. jxs 12/01/05 ir/jxs