Vktech&reg; LCD GSM 900Mhz Mobile Phone Signal Booster Repeater Amplifier + Antenna Kit Note: before bide, please make sure your SIM card support GSM 900MHZ, if not support, this item can not working. This type can cover about 200 SQM. A mobile phone signal repeater provides the ultimate solution in any area where cellular communications can not work well due to leak of signals. A mobile phone repeater is ideal for house, home, office use. Please take care the booster's functions is only to amplify the cellphone signal, do not create the cellphone signal, so if you cannt have a stable 2-3 bars in your cellphone at the place you want install the outdoor antenna, the booster maybe do not work well or even do not work. So In the case we suggest you donn't buy this item.