This Master Airscrew 12x7 Scimitar S-2 Profile Propeller is from Windsor Propeller Company"s Antique Series. FEATURES: The Scimitar Series features a high performance Scimitar shape with swept-back, narrow tips & undercambered blades The Scimitar shape generates greater thrust at lower rpm, resulting in less noise Made of lightweight, Black, glass-filled nylon Follows designs made by Tony Fokker in 1918. A terrific finishing touch on an antique aircraft with a four-stroke engine Propeller is totally fuel-proof INCLUDES: One 12x7 Antique Scimitar Propeller SPECS: Propeller Diameter: 12" (305mm) Propeller Pitch: 7 Hole Diameter: 0.246" (6.26mm) REQUIRES: Depending on the engine crankshaft size, the propeller may need to be reamed to a larger size using GPMQ5005 (SAE) or GPMQ5007 (Metric). Master AirscrewPart MASMA1270S