How do they work?
Light sensor alerts LED to come on only in darkened conditions. This helps prevent the LED from activating in lighted conditions when you don't need it, significantly extending battery life.
Powered by 2 replaceable lithium batteries that are included in each slipper. 
Weight sensors alert the LED in each slipper to activate. Each LED is angled upward for projection of light. These remarkably bright LEDs will easily illuminate an area 20 to 25 feet in front of you. After removing the slipper, a built-in timer delays LED shut-off to allow time to see your way safely back to bed.
Comfortable, non-skid soles.