This is the 8.5x6 Master Airscrew Glass Filled Lightweight Electric Propeller. FEATURES: Made of flexible glass filled nylon Undercambered lightweight blades Designed for 400-550 electric motors INCLUDES: One propeller REQUIRES: Prop reamer (GPMQ5005) SPECS: Diameter: 8.5" Pitch: 6" COMMENTS: Propeller Sizing Chart Motor Size Propeller 400 - Direct Drive 6x3, 6.5x4, 7x4 400 - Geared 7.5x5, 8x4, 8x5, 8.5x6 550/600 - Direct Drive 8x4, 8x5, 8.5x6, 9x6 jmm 3/23/03 ir/jxs