Reusable Revolution RR-558233 Solar Standard Road Stud, Blue LED Automatically illuminates when night falls or with the onset of inclement weather, constant on only, no switch Maximum load/Compression capacity: 30 tons 6 LED's provide up to 18 hours of light and has a visual distance of 800 yards Rechargeable Ni-MH (1200mAh) battery included, non replaceable Dimensions of 4.3" x 3.9" x 1.2" (LxWxH)