Cellphone-Mate CM-EFLEX-65 Flex Pro 3G Adjustable Cellphone Booster for Home Or Office (CMEFLEX65) The EFlex 65 Premium Signal Booster Kit is one of our most popular systems. This dual-band kit will boost most carrier's 2G and 3G networks over an area of up to 10,000 sq ft depending on your outside signal strength. It supports multiple carriers and phones/data-cards simultaneously so it's perfect for homes and small offices.