LOHOME(TM) Ultrasonic Mosquito Repellent Pest Bug Repellent Insect Keychain The mosquito repellent uses an advanced sonic frequency to repel insects and mosquitoes and make outdoor living and activities more enjoyable. 2 different settings available: 1=Mosquito (silent) and 2=Dragon Fly (very slight sound). Powered by 1 x CR2032 button cell battery (included). Red LED flashlight integrated into key ring. No chemical, no vapor, no odor, no pulverizer. Great for fishing, camping, hiking, jogging, golfing activities or simply enjoying your patio or porch day or evening.