Babolat Pop

Babolat's Play connected tennis rackets have been on the market for a while now, but that means little if you're hitting a different brand of racket. The Babolat Pop lets you keep track of your game simply by swapping it with the wristband you're already wearing. Its tiny, lightweight sensor keeps tabs on your shot types, swing speed, spin and style, all of which get combined into something the company calls a PIQ score, as well as your court time and number of shots. As you'd expect, it syncs with a companion app so you can compare scores against friends and friendly foes across the world, and is compatible with any brand of racket.