This is the Traxxas XL-5HV 3S Waterproof Electronic Speed Control. HV stands for compatibility with the high voltage 3S LiPo battery packs for greater efficiency and power. In addition to the three standard profiles (Sport, Race and Training Mode), the XL-5 HV features a Trail profile that serves up a little bit of drag brake for smooth intuitive driving for most of your adventures. A new Crawl profile introduces hill hold and instant reverse for extremely technical courses. Either will help you navigate the trail with ease.