Features: The principle of mosquito repellent: the bracelet achieves the effect of repellent mosquitoes by imitating the sounds of female mosquitoes, such as the sounds of male mosquitoes and dragonflies. In nature, the bloodsucking female mosquitoes are all at the stage of conception and spawning. At this price, Female mosquitoes will prevent male mosquitoes and avoid secondary conception. So the sound of male mosquitoes can achieve mosquito repellent effect. Product features: Pure physical mosquito repellent, non chemical mosquito repellent, safer, safer, more environmentally friendly, and healthier. Can be worn by the elderly, children, pregnant women and pets. The product can be worn indoor and outdoor (sea, park, Camping, climbing, fishing). Through physical expulsion, this product uses the frequency of microcomputer sound waves to surround 360 degrees, emits sound waves, electromagnetic waves, bionic waves, etc. to interfere with the hearing system and nervous system of mosquitoes to interfere with stimulation and escape from anxiety. Safety and energy saving, long battery life, intelligent chip drive, low power all day operation, power saving, no radiation. Package Includes: 1x Mosquito Repellent Bracelet 1x Charging Cable 1x User Manual Specifications: Material: ABS+Metal Size: As Picture Shown Color: White/Black/Pink/Blue Item model number: M30 Function: Sonic mosquito repellent Output: 34Hz-70KHz Charging time: about 30 minutes Battery life: 150 hours note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks for your understandings.