[Ultrasound] Wrist straps use high-frequency, unobtrusive sound waves to create a sound barrier, protecting you from mosquito bites. [] Say goodbye to messy and greasy mosquito repellent and spray. This acoustic wrist strap can keep away from mosquitoes without harmful chemicals and can be used in daily life. [Adjustable length] The mosquito repellent bracelet is fully adjustable, and each hole is easy to fit, making it perfect for adults and children. Wide application range : The pest control belt is very suitable for outdoor activities or indoor use, such as travel, gardening, barbecue, hiking, fishing, etc. The electronic mosquito repellent also supports electronic clock and temperature measurement functions.