This is a 15x6E Thin Electric Propeller from Advanced Precision Composites. FEATURES: Gray composite one-piece construction INCLUDES: One 15x6E Thin Electric Propeller with 0.128, 0.158, 0.197, 0.237 and 0.313" adapter rings REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. May need prop reamer, use GPMQ5005 (SAE) or GPMQ5007 (Metric) SPECS: Diameter: 15" Pitch: 6 Hub inner diameter: 0.25" (6.35mm) COMMENTS: For electric use ONLY. Do not use with gasoline or nitro powered aircraft. jxs 02/01/07 ir/jxs