This is a 17x4W 3D Fun Fly Composite Propeller from Advanced Precision Composites FEATURES: One-piece construction, gray in color INCLUDES: 17x4W 3D Fun Fly Composite Propeller REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. May need prop reamer, use GPMQ5005 (SAE) or GPMQ5007 (Metric) SPECS: Diameter: 17" Pitch: 4W Hub Inner Diameter: 0.28" (7.2mm) jxs 06/17/10 ir/jxs