For athletes and outdoor adventurers who want the ultimate in a multisport on-wrist trainer, the ultra-rugged fenix 5X Plus is here. It’s our first fēnix series watch to offer a wrist-based Pulse Ox Acclimation sensor, a non-medical device that provides estimated blood oxygen saturation awareness at high altitudes. Other highlights include routable color TOPO maps, estimated wrist-based heart rate, a music player that lets you store and enjoy up to 500 songs.