MMA Rash Guard - Short Sleeve, Black, Small Oval from Piranha Gear We first intended these for people that practice MMA or UFC mixed martial arts... but they work just as well for Karate, Judo, Aikido, and general grappling for under your uniform or just plain. Not to mention people we know using them for SCUBA or in the pool... Flat sewn seams make them more comfortable no matter what. We even have a special side panel insert that keeps your armpit from chaffing.