Features: Ultrasonic smart mosquito repellent watch, 3-in-1 use, temperature measurement, time display, and mosquito repellent. Pure physical mosquito repellent, free of toxic chemicals, safe and environmentally friendly. Fast charging, long battery life, ensures 5 days working time and 6 months standby time after it is full charged. Bracelet design, easy to carry, suitable for beaches, parks, camping, mountaineering, fishing and other places to use. Three modes to choose simply press the switch button, applicable to indoor and outdoor use. Specification: Model: M20 Type: Mosquito Repellent Wristband Color: Black, White(Optional) Input: 5V/1A Frequency: 34Hz-70KHz Battery: 3.7V 90mAh Polymer battery Charging time: 30 minutes Package Size: 10 * 6 * 4.5cm / 3.9 * 2.4 * 1.8in Package Weight: 50g / 1.8oz Package List: 1 * Bracelet 1 * USB Cable 1 * User Manual