about this project ULTRASONIC TECHNOLOGY: Using biological sound waves (ultrasonic wave + bionic wave), the double wave ring overlaps and plays sound, which can imitate the sound of female mosquitoes (male mosquitoes and cockroaches), so as to achieve the mosquito repellent effect. Safety: Our electronic mosquito repellent wristband, ultrasonic waves create a sound barrier, purely physical mosquito repellent, no chemical substances, safer, more environmentally friendly, more reassuring, healthier, the elderly, children, pregnant women and pets can all wear it. USB charging: Smart charging anti-mosquito bracelet, built-in smart chip, USB fast charging, 30 minutes of charging, 30 days of standby time, 150 hours of use, saving time and trouble, effectively avoiding more than 90% of mosquitoes. Three modes: press once to turn on the switch to start indoor mode; press again to switch to outdoor sports mode; press the third time to turn on silent sleep mode; press the fourth time to turn off the device WIDELY USED: Whether you are camping fishing hiking or park jungle shopping, Smart Mosquito Repellent Free is the best jungle formula insect repellent, as a baby swim float or rain cap waterproof adult wear it on a camping bed kids camping chair or toddler Swimming Aids It's Basic Kids Bike Accessories Good Body Panels.