The Digital Antenna PowerMax is a high powered cell phone repeater for small buildings. Perfect for use inside homes and offices where cell phone service is poor or non-existent, the 4KSBR-50U repeater system brings the outside cellular signal indoors and amplifies it. This complete kit includes everything you need to improve cell phone reception over an area between 3,000 and 5,000 sq. ft. Depending on conditions the complete repeater system will typically penetrate 2-3 interior walls and 1 floor. The system also comes with an in-car power supply - allowing the PowerMax to be used in trucks, RV's and large boats. We would recommend that you take a look at the DA4KSBR-50M Cell Phone Amplifier, which is designed for use in an RV or boat.