1) Uses high pitch sound waves to keep away mosquitoes. Almost silent, you won't notice it working. 2) Working frequency: 8.5-10 KHz / 40-50Hz 3) Built-in LED red assistant flashlight. Power: 2 x CR2032 battery. 4) Three Settings: 0 = OFF, I = Male Mosquito (silent), II = Dragonfly (very slight sound), lll=Bat 5) Covers a 6 to 8 feet (1.8 to 2.4 meters) range. 6) Keeps on working for about 160 hours continually when fully capacitance with sun day charge 7) Environment-friendly, no smell and harmless to human beings, pets and plants. 8) With keychain, easy to carry. Or clip to your bag, clothing, backpack, and tent. 9) Ideal and reliable companion for camping, hunting, fishing, farming, and sleeping. 10. Use it anytime anywhere - no chemicals! Keep it on your key ring and simply switch the on button to produce a high frequency sound effect which keeps mosquitoes and other flying insects away! 11. Unit size: 5.7 x 4.0 x 1.5cm 12. Packaging: 120pcs/ctn.