Sun Timer Watch

From the website:

Sun Timer Watch

The ultimate UV ray meter — and a whole lot more.

Simply enter your skin type and sunscreen SPF into this ingenious device and it tracks your sun exposure and alarms you when you need to get out of the sun.

Also functions as a watch, stopwatch, and alarm.

• Adjustable band: wear on your wrist or arm, or attach to a backpack or stroller

• Dynamic readout darkens or brightens according to available light

• Waterproof down to 32.8' (10 meters)

• Made by Minox of Germany

• One size

$48.95.