The UVSunSense Wrist Band works by detecting dangerous UV rays. Courtesy photo.

Sunscreen can be confusing.

There's all the different brands, various SPF numbers and forms to consider -- and even when you find one that you like, the question of when to reapply continues to be a guessing game.

"Even the most responsible people who are vigilant about using sunscreen -- and especially those who apply it to their children -- are at the mercy of factors such as the environment and even the shelf life of their sunscreen," says dermatologist Dr. Jody Levine of Plastic Surgery & Dermatology of NYC.

But a new wrist band created by a nuclear physicist is claiming to take the guesswork out of reapplication with its ability to detect and measure the strength of dangerous UV rays.

After you apply your sunscreen of SPF 15 or higher on your face and body, UVSunSense instructs to also apply the sunscreen to the wrist band, and wear it as you enjoy the beach, backyard barbeque, outdoor sports and even dipping in and out of any kind of water.

The band starts off as orange, and immediately turns purple when exposed to sun rays, which lets you know that it has been activated. When the band turns dark brown, that's your cue to reapply sunscreen. And if the band turns a pink salmon color, it's a warning that you've received the daily limit of UV radiation and should take cover in the shade.

The goal is to prevent cancerous sun exposure, sunburn and even sun poisoning.

A pack of seven retails on for $6.99; we think the peace of mind it creates is priceless.