Mole repellent ultrasonic unit vibrates and emits 400 to 1000 hertz low-frequency sonic pulses every 30 seconds to repel burrowing rodent. The ultrasonic gopher repellent irritating moles, gophers, chipmunks.In general, it need about 2-4 weeks to drive the away from your garden, Then your garden will be free of these nuisance critters after some weeks.Solar-Powered Mole Deterrent: This Mole repellent is charged by its solar panel. 4-hour solar charge lasts for 5 days working, no need to replace battery. The solar panel is protected in a waterproof ABS plastic housing.Each mole repellent spikes operates in a circular pattern, approximately 40 ft.It is recommended to use multiple in severely affected areas to achieve a best effect. Make use of our mole spike unit package available in 4 pieces so you can cover small to large properties like lawns, yards, gardens, farms & moreEasy to use. Just dig an 8 hole, then insert the device 2-4 above the ground. Leave the repeller out to the sun