Size: 5.5 * 3.5 * 1.4cm Charging time: 30 minutes Working hours: 150 hours Mosquito repellent principle: The bracelet achieves mosquito repellent effect by imitating the unpleasant sounds of female mosquitoes, such as the sounds of male mosquitoes and dragonflies. In nature, female mosquitoes are the ones that suck blood, and they are all in the stage of conception and spawning. During this stage, female mosquitoes will avoid male mosquitoes and avoid secondary conception. Therefore, simulating the sound of male mosquitoes can achieve mosquito repellent effects. Product features: Pure physical mosquito repellent, not chemical mosquito repellent, safer, more reassuring, more environmentally friendly, and healthier. Elderly, children, pregnant women, and pets can all wear it. The product is portable for indoor and outdoor wear (suitable for beach, park, camping, hiking, and fishing). ATTENTION: It is strictly prohibited to cover the product with clothes during use.