This product is wireless, and doesn´t need to be installed. Customers can get best service in short time and with least manpower. It can be used in many occasions, like restaurants, hospitals, bloodmobile, ticket offices, amusement parks, banks financial center, and so on. The product includes one main device and Install up to 998 service calling systems, also there are 16 types of ring tone ***ions for you to choose. This product comes with a rope for service calling systems to fix on tables and so on.