Tracking your fitness is important. Wrist-bound notifications are handy. Yet you don't want to give up your favorite watch. With the Chronos Smart Watch Disc, you don't have to. It mounts to the back of nearly any timepiece, so it's hidden from view, and is only 3mm thick, so it's comfortable to wear. It gives you vibration and LED-based lighting alerts for incoming notifications, lets you dismiss or respond via taps and/or gestures, and also uses its accelerometer to track your steps and movement. All with nary a screen in sight.