Oregon Scientific recently released a "Portable UV Sensor" which monitors incoming UV rays and can calculate exposure time based on the SPF of your sunblock.
- Know when to protect yourself and your family from harmful UV rays with this compact, stylish UV monitor
- Exposure timer uses UV, SPF and skin type to calculate recommended exposure time, and updates automatically with changes in UV intensity
- Monitors current UV levels and temperature and has a built-in digital clock
- Includes one CR2032 coin battery and easy-close carrying strap
No word on waterproofness but an interesting gadget non-the-less. Would be helpful for me on cloudy days when I forget to put on sun screne. I always get deceived by clouds...
At only $19.99, it won't break the bank.
More info: amazon.com