Automatic frequency conversion technology: The ultrasonic pest repeller uses the latest automatic frequency conversion technology to generate different ultrasonic bands and constantly change the frequency so that pestsand mice fail to develop immunity or adaptability to insect repellents. The insect screen is easy to install and connect. The effect lasts 3-4 weeks. The ultrasonic repeller is ideal for homes, offices, garages, attics, basements, warehouses, greenhouses, gardens, hotels, etc. Wide Coverage Area: Each ultrasonic insect repellent has an effective range of up to 1600 square feet. It is recommended to install this ultrasonic insect repellent vertically 32-47 inches above the ground and have an ultrasonic insect repellentin each piece will help you get the best results. Thanks to the latest ultrasonic technology, you can get rid of the pest in a simple and easy way. No chemicals, non-toxic, no smell and noise. These pest repellents are suitable for kitchen, bedroombedroom, basement, garage, warehouse, etc. Using ultrasound to remove parasites is a process that will likely take around 3-4 weeks to clearly show the effect.