Scooblite Reusable Glow in the dark stick

I was sitting watching for some diving equipment and found a new cool glow stick from a company called Scooblite, which they claim can glow for hours, even days.

How is this achieved? This is what I found on their website

http://www.scooblite.com/what-is-it.html

How Does it Work? The Patent Pending technology provides a new way to capture the glowing photons, which are produced via crystal manufacturing from the earth’s resources of strontium, aluminum, and other rare earth elements. When exposed to other light sources the crystals quickly absorb the light, store it, and then produce enough light to continue glowing for hours or even days. It takes glow-in-the-dark technology to a whole new level.

Is there anyone here that can tell me how they get it to glow for so long?