Mosquitoes that suck human blood are female mosquitoes after mating to prepare to lay eggs. These spawning female mosquitoes instinctively avoid male mosquitoes. Our portable mosquito repellant mimics the sound frequency from the wings of male mosquitoes and that prevents from female mosquitoes approaching. Also, the natural enemies of mosquitoes are dragonflies. All mosquitoes are afraid of dragonflies so they never approaches to them. Our portable mosquitoes repellant mimics the sound frequency from the wings of dragonflies so it repels blood-sucking mosquitoes. - No smell. no smoke. and no need to spray and spread as this uses ultrasound. - It clips on anything you carry with including belts, bags, and clothes. - Portable mosquito repellant is environment-friendly and protects nature as it contains no chemical substances nor any insecticides.