Additional handset for BT Elements 1K Up to 1km Outdoor Range 50 Number Calls List Splash and Dust Proof BT Elements 1K Weatherproof Additional DECT Handset Please note that this is an additional handset and charging cradle to be purchased for use with an existing system. This handset cannot be plugged into a telephone line, and will not work without a base station (The BT Elements 1K main unit with base is Up to 5 handsets can registered to the base of the BT Elements 1K. Benefits of using multiple handsets include features such as: intercom, call transfer, conferencing, and shared phonebook.