This is a doze alert device that helps prevent fatigue related automobile accidents.It's wearing on the ear of a driver and works on the principle of electronic balance.If you start to nod off while you are driving and your head falls forward,the smart nap-zapper will buzz in your ear and help you avoid the danger of fallingasleep at the wheel. The alarm is not only designed to keep you woke until youget where you are going, but to alert you to your drowsiness so that you cantake corrective actions. Change drivers, take a break (eat and drink) or take anap.The alarm is about the size of an external hearing aid and weighs about 16g. It fitssnugly around one ear and will stay in place even when glasses are worn. The alarm monitors the position of the driver's head. It gives out sound at the presetangle. If the driver's head drops forward far enough, the alarm goes off. This positionat which the alarm will sound can be adjusted. For example, if your normaldriving posture is with eyes and chin pointed down, the device can be set to toleratethat, but will sound off if the chin drops below a certain point. A gravity switch insidethe alarm monitors the angle of the driver's head. Usually, drowsiness will sneak up on you unawares. Nap-zapper will assist you inthat area. Stay alert, stay alive, and nap-zapper.Working principle:Our patent product, electronic balanced anti-drowsy alarm, which is popularly callednap-zapper, is a high-tech product that works on the principle of electronic balance.It fits on the ear of a driver when he is drowsy or on a long trip. Once adriver feels sleepy during his driving and his head nods forward, the alarm willbeep to arouse the alert of the driver and the passengers. It stimulates the nerveto be exciting and eliminates the sleepy feeling, therefore, avoid traffic accidents.It's light-weight (16g) and comfortable enough even with glasses.Technical index:1) Alarm sensibility: alarming angle is: 15 - 20, (adjustable)2) Rated voice pressure: 110DB3) Power source: DC 6V (AG 12 x 2)4) Working current: 0 (not in alarming state), less than 25Am (when in operation)5) Color: silver gray, yellow, green, and red 6) Dimensions: 75 x 46 x 1mm7) Weight: 16g8) Life span of battery: 1 year Inner packing: Blister packaging or leather packaging with color boxOuter packing: 200pcs/ctnCarton size: 39 x 33 x 29cmWeight: 12kg