What is cups with holes in the bottom?

Cups with holes in the bottom are specially designed to drain liquids. They are commonly used for drinking water while playing sports, camping, or hiking. The holes in the bottom allow air to enter the cup when drinking, which helps the liquid to flow out smoothly without creating a vacuum that can make drinking difficult. These cups are usually made of plastic or stainless steel and are lightweight and durable. They are available in various sizes and designs and can be easily cleaned and reused.