Don't Fall a Sleep While Driving Cool Gadget If you are not satisfied with your purchase, simply contact us via eCRATER message and your interests will be protected. Please don't open a dispute or leave neutral/negative feedback without communication. Thanks. Anti-Sleep Alarm is an innovative, potentially lifesaving anti-drowsiness / tiredness alarm. You just wear behind the right ear it works on the principle of electronic balance. Working Principle：It is worn over the ear and has an electronic position sensor. When your head nods forward, it sounds a loud alarm to instantly wake you and alert your passengers. Features:1. Driver safety alarm to help prevent accidents caused by falling asleep at the wheel.2. Brand new anti-sleep alarm for drivers!3. Perfect for anyone who needs to keep alert on duty, like drivers, guards, machine operators, and even students4. Safe for long drive and drive at night.5. Especially suitable for long-distance driving or night driving6. Easy to use and comfortable to wear for a long time.7. Work on the study of human body balance8. Main Function: Anti Sleep Alarm9. Alarm mode: sound alert10. Dimensions:80 x 22 x 15mm11. Battery: button cell battery(Included)12. Life Time: 30,000 nods Package include:1x Don't Fall a Sleep While Driving Cool Gadget