The United States Tennis Association (USTA) bans the wearing of Apple Watches during competition. The thinking is that you could be coached from afar, providing an unfair advantage. But Florida-based inventor Peter Springer reckons that a competitive event is precisely when a serious athlete would want their physical stats tracked. He thus designed this Robin Clip, which allows you to secret an Apple Watch on your body, with the sensor pressed against your skin (and the face not visible). The Robin Clip is also handy for tracking one's fitness in situations where you don't want to, or cannot, wear a watch (combat sports, for example). The gizmo is made out of silicone, with a steel spring clip. Springer is currently running a Kickstarter, with 10 days left to pledge at press time. The Robin Clip runs $25.