Designed for power-hungry drivers who push their Sledge to the extreme, the heavy-duty 52-tooth Mod 1 (1.0-metric pitch) spur gear is machined from hardened steel for extra-long life. Traxxas spur gears let you fine-tune the performance of your Traxxas model. Changing gear ratios can help balance acceleration and top speed for different running conditions. Please consult your owner's manual for more information on recommended gearing options for your specific model.