Boom Racing #BR648027 Heavy Duty Bevel Helical Gear Set 43T/13T Underdrive For All 1/10 Axial Trucks for Axial Yeti Lightweight upgrade instantly enhances overall performance in handling and durability. Heavy duty bevel helical gear set - 43t/13t underdrive gearwhy? Hd gears instead of stock "softer&rdquo; metal. Helical shaped teeth: more contact between teeth. Spiral cut gears run quieter. Increases traction when combined with stock gears or over-drive gears in front axles. Benefits:use the gears in different combinations front and rear to reduce torque twist in the rear and overdrive the front axle to help pull you. . . More details below. Takes 7 to 15 business days by standard airmail shipping. 80% of packages arrive within 10 business days. Most packages ship within 12 hours. Please allow 1 extra day if order is placed during the weekend. Expediated shipping is shipped by dhl or fedex. Arrives in about than 2-5 days. Major cities will receive orders earlier.