Knee pads are the most important personal equipment for mountain bikers, second only to helmets. The status of elbow protectors is relatively lower, and many drivers do not like to wear them, but it is still best to wear them during cycling. Knee and elbow pads can be mainly divided into hard and soft shells. In the past, traditional hard shell knee pads and "endangered" knee pads have been replaced by composite knee pads that combine hard shells and internal cushioning materials. These types of knee pads are still designed for aggressive cycling.