The pest stop mole repeller is 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 it will not affect h