Gizmag has featured a number of GPS based location devices and concepts that are designed to keep track of your most loved people, pets and possessions. From the Nu.M8 child watch system, to a GPS dog-collar device or a range of tracking devices capable of following just about anyone or anything. The latest in an ever expanding range of these gadgets - the Ekahau wrist-tag, is a tracking device that allows monitoring via a Wi-Fi network. When will it end? Not anytime soon - Jude Garvey checks out three different tracking systems on (or soon to be released on to) the market.