Our company Shenzhen Tangreat Technology Co., Ltd�is a professional and well-experienced company in R&D, manufacture and marketing of spy bug detector, signal jammer, and GSM mobile signal repeater, Which is widely used in Military, Police, Army, Prison, school, and other security department, and We have cooperated with telecom company from different country, and also got good reputaion from our customer with good quality and reliable sale service.