Mighty Mule F3101MBC Wireless Intercom Keypad Additional Intercom Base Station Unit Ideal as a replacement base station or as an additional base station for the Mighty Mule Fm136 Allows the homeowner to speak and screen visitors from the safety of their home with a 500 ft. Reception capability Up to four indoor base stations (F3101MBC) can be utilized to operate with the Fm136 wireless intercom keypad Not for use with the Mighty Mule Fm137 digital keypad or mmkpd weatherproof LED wireless keypad Backed by a 12 month Mighty Mule warranty and technical support