Solar Cynergys initial outdoor product is a brick that is installed in the ground and covered by a polycarbon shield strong enough to drive a truck over. During the day, the solar cell inside soaks up sunlight, storing the energy in its capacitor. At night, the light comes on automatically. A single day of weak sunlight is enough to power the LED for several days, and the lights can last as long as 25 years. A built-in photo sensor automatically activates each light at dusk and turns it off at dawn.The lights can be set into stonework, gravel, or even soil to provide accents or create a safe walk or driveway. Comes in packs of six.Warranted for 10 years, 25+ years life.