Mobile phone universal that is needless to say it, and now even a few years old children have a mobile phone to say adults. Some people may have several mobile phones, a mention of the phone will have to mention the headset. We often take the headset is on the side of things we used it to study, listen to music, listening to the radio. The main body of the earphone is a circular closing coil, which is connected with a mobile phone and a black cylinder shaped sound receiving device. The closed circular coil placed under the neck, then the circular coils of wire connected to the earphone of mobile phone online, then the receiver of a soybean grain size plug after the pierced ears, a pair of headphones can use. Circular coil is now applied to all fields, the combination of the headset can not be missing a circular coil. The use of circular coil in the future is more and more widely. This will make the circular coil market demand is growing