Whats the difference between Under Armour and a rashguard?
Under Armour makes gear that is intended to be worn under athletic uniforms (under shoulder pads in American football, under jerseys, etc). While the fabrics they use are often similar to the fabrics used in grappling rashguards, they tend to pill up faster and the seams aren’t as durable. Also, given the price of Under Armour, you aren’t going to be saving any money by getting one of their products instead of a rashguard intended for grappling. If you decide to go with Under Armour, make sure you get their Heat Gear line of products and not their Cold Gear line.