This is a Master Airscrew 7x5.5 Glass Filled Electric Propeller. FEATURES: Made of flexible glass filled nylon Undercambered lightweight blades Designed for 400-550 electric motors INCLUDES: 7x5.5 Glass Filled Electric Propeller REQUIRES: Prop reamer (GPMQ5005) SPECS: Diameter: 7" Pitch: 5.5" 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 updt jxs 7/01/03