This is a 18x6W Thin Composite propeller from Advanced Precision Composites. Designed for 3D Fun Flying. FEATURES: Gray composite one-piece construction. Comes in a bag attached to a header card. INCLUDES: One APC 18x6W 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: 18" Pitch: 6 Hub inner diameter: 0.30" cdh8/26/03 ir/jxs