Sennheiser AB 4 - The AB 4 is a filtered, inline antenna booster module with BNC connectors, designed to offer +10dB of boost to compensate for signal losses created by long antenna cable runs

The AB 4 is a filtered, inline antenna booster module with BNC connectors, designed to offer typ. +12dB of boost to compensate for signal losses created by long antenna cable runs. The AB 4 is fully compatible with all legacy evolution wireless systems. Additionally, the AB 4's filters have been expanded to support the bandwiths up to 88 Mhz.