It's great if you've got candles placed throughout the house that might prove helpful in the instance of a power outage, but what good are they if you can't see them in the darkness? The Blackout Candle is a electricity-less lighting solution that's intended specifically for this scenario.
The wax material of the Den Studio product is made from a mixture of paraffin and glowing powder. During the day, the rectangular candle soaks up the light cast upon it, storing it so that it can use the energy to illuminate in the night. So long as you keep the luminary exposed, it will perform its function reliably and be effectively discernible after dark.
For added convenience, the Blackout Candle has had a notch cut out of it so that a box of matches can be kept handy.