Description:- Mosquito repellent bracelet is adjustable, (One size fits all) enough to wear children and adults.- This sonic wristband prevents mosquitoes from biting without producing harmful chemicals, odors or smoke.- Smart USB charging drive mosquito bracelet, a bracelet to let you worry-free through the whole summer, farewell to mosquito troubles.- Whether you are camping, fishing, hiking or parks, shopping, smart mosquito repellent bracelet is the best mosquito repellent. Specification:Model: M1Function: Ultrasonic mosquito repellent3 Modes: Indoor, Outdoor, MuteInput: 5V/1AOutput: 34Hz-70KHzCharging time: about 30 minutesLife time: 130 hours