Ultrasonic wristband for mosquito protection and insect controlULTRASONIC TECHNOLOGY: By using biological sound waves (ultrasound + bionic waves), double wave ring overlapping sound playback, you can imitate the sound of female mosquitoes (male mosquitoes and cockroaches), thereby achieving mosquito repulsion. .SECURITY: Our electronic mosquito repellent bracelet, ultrasonic to create a sound barrier, pure physical mosquito repellent, without chemicals, safer, more environmentally friendly, safer, healthier, than the old, children, pregnant women and animals can carry. .USB CHARGING: Smart charging mosquito repellent bracelet, built-in smart chip, USB fast charging, 30 minutes charging, 30 days standby time, 150 hours use, save time and trouble, effectively avoid more than 90% of mosquitoes. .THREE MODES: Press once to turn on the switch to start indoor mode; press again to change outdoor sports mode; press again a third time to activate silent standby mode; press a fourth time to turn off the device.