By David Ponce

Racing is pacing. Whether it’s automotive or human powered, there’s more winning to be having when you know how to pace yourself properly and aren’t constantly accelerating and decelerating. Keeping your inertia is key. And in the case of humans, keeping your stamina is also paramount; put too much at the start, there’s nothing left at the end of the race. If you happen to race underwater (or at least on water), the Tempo Trainer Pro is the waterproof metronome you’ve always wanted. Now with interchangeable batteries, it can provide you with several lifetimes worth of watery pacing. Should it come undone from under your swim cap, it’ll just float right up to the surface.

It’s $50.

[ Tempo Trainer Pro ] VIA [ Coolest Gadgets ]