In modern sports, the use of knee pads is very extensive. The knee is not only an extremely important part of the exercise, but also a vulnerable and vulnerable part. It is also a situation where the pain is extremely painful and the recovery is slow, and even individual people may appear cloudy and aching. The “knee protectors” of thick felt materials that can be purchased in almost all sporting goods stores can reduce and avoid injuries to a certain extent. In winter, they can also play a role in preventing cold and are inexpensive. This is not the recommendation of “knee protectors” as a must-have item, but it is also true that all sports activities are widely used.