What is a rash guard top?

A rash guard top is a type of shirt that is designed to be worn under a wetsuit or other water sports clothing. It provides protection against rashes caused by abrasion against the skin, as well as from the sun's UV rays. Rash guard tops are typically made from a stretchy, synthetic material, such as nylon or spandex. They are often designed with flatlock stitching to reduce chafing, and some models also feature mesh inserts for breathability. Rash guard tops can be worn by both men and women, and are available in a variety of colors and styles.