Swim cap keeps water out of your ears. Wear it over your ears. The lower part of the ear is lower than the regular cap so it is easier to put on. Wear it under a cap that is brought to you by racing, and it can also be used as a cold protection. It also prevents water from entering your ears, so it is recommended for regular pool practice. Depending on the usage situation, there may be some water intrusion, so if you are worried about water intrusion in your ears, please use the ear plugs together with this cap (ear plugs are not included).