GREY&GOLD CNC ALUMINUM & HIGH CAPACITY SPOOL:Comply With The Characteristics Of Aerodynamic Rotation Centrifugal Force To Decrease Air Resistance, And Fashion,Rotation More Silky Smooth. STABLE PERFORMANCE-:4.8:1 GEAR RATIO.Japan Imported Stainless Multi-Tooth Gear Design, Increase The Overlap Between Gears, Reduce The Wear Of Gears, More Durable, While Increasing The Transmission Between Tooth Pitch And Tooth Pitch, To Play The Maximum Torque Force.