An Internal Gear Hub is a type of bicycle transmission system that houses its gears within a sealed unit. This design protects the gears from dirt and damage, making it low-maintenance and reliable. Riders can shift gears smoothly without needing to pedal, which is beneficial for navigating varied terrains. These hubs typically offer multiple gear ratios, allowing cyclists to easily adjust their pedaling effort. They are commonly found on city bikes and commuter bicycles, providing a practical solution for everyday cycling. The internal mechanism also contributes to a cleaner look, as it eliminates the need for an external derailleur system.