This is an optional Hot Racing Traxxas 48 Pitch Hard Anodized Aluminum Spur Gear. These gears are available in a variety of tooth count options. 

Features:

• CNC machined 6061-T6 aluminum construction
• Replaces stock nylon spur gear
• Hard anodized in light gunmetal color for durability and corrosion resistance
• Silver anodized countersunk aluminum washers
• High strength hardware

Specifications: 
Number of Teeth: varies 
Gear Pitch: 48 pitch 
Mounting Holes: 3 
Tooth Face width: ~5mm

Includes: 

• (1) 48 pitch spur gear
• (3) Mounting screws
• (3) Silver anodized countersunk washers
• (3) Washers (use as needed underneath countersunk washers to prevent screw ends from protruding too far through spur mounting plate)

NOTE:

• Aluminum gears are softer than steel and are intended for speed performance. For ultimate durability consider steel gears.
• Consider using Hot Racing motor lock plate HRATE18L06 for secure motor mounting
• Check gear alignment and secure you motor before running the vehicle
• Do not over tighten the slipper. Even metal gears may fail with a over tight slipper.
• Motor should no way exceed 180F (over 160F is not recommended). ESC should not exceed 160F. Excessive temperatures will shorten the life of the motor and ESC.