An advanced sonic repeller that drives burrowing animals away by emitting low frequency ground vibrations, which creatures such as moles interpret as signs of an approaching intruder. The unit emits a low frequency vibration every 15 to 20 seconds, which is transmitted through the soil. The effectiveness of the mole repeller can be affected by soil density; chalky or sandy soil will not transmit the vibrations as effectively as solid clay-type soil. Covers up to 9000 sq. ft. (about 836 sq. metres). Battery operated (4 x D cell batteries). Batteries normally last around 4 months. Safe and economical to run. Environmentally friendly - no chemicals or traps. The only mole repeller to include both a flower-bed cap, and a flat mow-over lawn cap. Will not affect humans,cats,dogs, fish or birds.