FlightScope Xi
Credit: Courtesy of FlightScope

If there's a problem with your swing, FlightScope Xi can help. The portable handheld device, with a built-in battery, connects directly to your iPhone, iPad, or Android phone or tablet via Wi-Fi and gives you real-time measurements on shot distance, precise landing position, club speed, ball speed and smash factor. You can see a virtual representation of your swing, and you can play FlightScope Skills challenges to make practice more fun and to track performance over time. [$2,500; flightscope.com]