Insect Repellent with Keychain, Suitable for Indoor Use, Travel, Trip, Camping and Fishing Ultrasonic frequency: 40±2kHz Power voltage: 110/220 V AC Ultrasonic wave generator Mainly for repelling mosquito, flying insects Composed of frequency carrier circuit, emitting hi-frequency ultrasonic 40±2kHz Stimulate mosquito, flying insects and damage their nervous system and so as to drive them out Built-in night light can work as normal lighting Suitable for indoor use, travel, trip, camping, fishing Caution: Prevent it from water and humidity To improve the mosquito repellent efficiency, please keep ultrasonic wave's emitting direction to these insects and effect will be better if there are no objects between human body and this generator 4 button cells With LED bulbs Efficient range: 3m2