about this projectULTRASONIC 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 deviceWIDELY 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.