The repeller unit is effective at repelling Rat， by emitting a sonic pulse which feels like a vibration transmitted through the ground. Rat then perceive a danger sign causing them to evacuate the area.The pulse is transmitted at approx 40-50 second intervals and covers an area of approx 625sq meters. The repeller transmitted its signal in all directions approx 15m so they can be placed approx 30m apart in high risk areas， it is always recommended to use two or more unites to get the best results.The sentinel repeller works with a solar charged battery. The solar module charges the battery during the day， and runs the unit while night-time operation is enabled by the battery.Specifications:Power supply: solar panel， and long lasting rechargeable battery by solar energyUltrasonic frequency: transmitting a combination of vibration and ultrasound waves every 30 seconds in the frequency between 400 HZ~1000HZEffective coverage: 6000 square feet or 650 square metersHeight: 19" tall from the bottom of the stake to the top of the solar panelFunction 24 hours a day， no operating costNo Poison， no chemical， environmentally friendly; safe even with pets and children around- Brand New and High Quality- Ideal pest Control Device to Keep Snakes away from your Garden or Lawns by Utilizing both Sonic Wave Sound and Vibration Technology.- Completely Powered by Solar Energy- Easy and safe to use. No Poison， No Chemical- Function 24 Hours a Day， No Operating Cost; no waterproof- Power supply: Solar panel， and Ni-Cad Battery Recharged by Solar Energy- Frequency: 400-1000 Hz- Sound: 30db- A Multi Pulse Repeller Keeps Changing the Ultrasonic Pulse it Emits， So Rat do not Get Used to it， and won't Come Near your Garden.- Effective Range:625sq Meters- Sound: 50dbNote:Firstly， please check the ground surface before using it. Frozen soil， irrigated or waterlogged ground is not suitable. Dig a hole into solid earth to place the device. The density of the soil will greatly affect the effectiveness of the device. The more solid the earth has the better efficiency the device will be.Package include:1x Solar Repeller