This is the Master Airscrew Nylon K series 12x4 Propeller. FEATURES: Designed for 4-stroke engines but works fine with 2-strokes as well Wider blades and thinner airfoil sections maximize efficiency for slower turning 4-stroke engines Constructed of glass filled nylon INCLUDES: One 12x4 Master Airscrew Nylon K series propeller REQUIRES: Installation on engine crankshaft If prop reamer is required the Great Planes reamer for standard size crankshafts (GPMQ5006), or Metric size crankshafts (GPMQ5007) can be used SPECS: Size 12x4 (30x10cm) maw6/19/03 ir/jxs