The Waterproof R30 Short Sleeve Rashguard ,A Rashguard, also known as rash vest or rashie, is a type of water wear, an athletic shirt made of Spandex and Lycra nylon. The name Rashguard reflects the fact that the shirt protects the wearer against rashes caused by abrasion. These shirts can be worn by themselves, or under a wetsuit. The use of Lycra and Spandex create a garment that is lightweight, quick drying, flexible, durable, naturally antibacterial and water wicking. Other important components of a rash guard include flatlock stitching, and a ten panel construction. Ten panel construction versus the conventional 4 panel tee shirt construction enables the user increased mobility wet or dry. Rashguards also offer protection from the sun (measured by its Ultraviolet Protection Factor), the Waterproof Rashguard offer a 50% UV protection factor. Features: Long and Short Sleeve Versions. +50 UV Block. Spandex Lycra. Bonded High Quality Nylon thread.