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 & more ^Easy to use. Just dig an 8 hole, then insert the device 2-4 above the ground. Leave the repeller out to the sun for 24 hours to be charged before used.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 ^Note: Although the solar mole repellent is waterproof, it cannot be immersed in water for a long time, which will affect its service life. When encountering heavy rain or rainstorm weather, please take it out of the ground first, wait for the accumulated water to dissipate, and then put it in the soil.^