Ultrasonic repellents are the only lasting solution to your mole problem. You can kill your resident mole, but if your garden remains an attractive environment, another one might move in. Ultrasonic repeller devices work by emitting low frequency bursts of vibrations into the soil. The moles confuse the vibrations for the movements of predators or other moles, and hence quickly vacate the area, moving to other parts of their tunnel network.