The shorts are built with a material that provides UV protection of 30+. The seams are sewn with flat-lock stitching which won't leave marks on your skin. The rash guard shorts can be worn as a standalone for protection from UV, biting, and stinging critters or its perfect to wear underneath your suit. When worn under your exposure suit, the Sleek material 85% Polyester and 15% Spandex makes the suit slide on easy and adds additional thermal protection. It's not only for diving and is ideal for all kinds of water sports. UV protection 30+, cool lightweight material, flat seam construction for comfort make the Mares Trilastic Shorts a must for the active water sports enthusiast. The Mares Men's Rash Guard Trilastic Shorts is popular because customers like the following qualities of the Mares Men's Rash Guard Trilastic Shorts: Breathable, Comfortable, Dries Quickly, Durable, and Easy To Put On And Off.