Solarrific&reg G4040 Solar Mole Repeller Effective at repelling burrowing pests such as moles, gophers, and other rodents by emitting a sonic pulse, which pests find extremely piercing, thereby repelling them. The vibrating sonic sound pulses at 50-second intervals and covers a surface area of over 6000 sq. ft The solar cell charges the battery during the day (even works under cloudy conditions!) and runs the unit &reg while night time operation is enabled by the high efficiency battery