This item is placed on the backside of the mobile phone near the internal antenna. It??suitable for GSM mobile phones with an internal antenna and the available frequency should be 900-1800MHZ. When there is a phone call coming the inside LED lights flash very beautifully. At the same time it??good for your health because it can reduce the radiation from the mobile phone effectively. There is no battery needed and your logo, design or slogan can be printed on its surface which makes it an ideal product for advertisement and promotion. It??packed with an OPP bag and can be sold in the marketplace. OEM service is available. We can make samples and carry out mass production exactly per your size and design.