A spur gear is a type of gear characterized by its straight teeth that are parallel to the gear's axis. These gears are commonly used in various mechanical devices to transmit power and motion between shafts. They are efficient and simple in design, making them a popular choice in applications like clocks, bicycles, and machinery. Spur gears can be found in different sizes and materials, allowing for versatility in their use. When two spur gears mesh, they rotate in opposite directions, which helps in transferring torque effectively. Their straightforward design contributes to their reliability and ease of manufacturing, making them essential components in many mechanical systems.