The Panasonic KX-TGP600 is a SIP Dect Cordless handset & base unit set. The system works with your KX-TPA60 and KX-TPA65 phone systems. The device gives you the option to add upto 8 additional handsets. The device keeps your calls secure through its SIPS/SIP-TLS technology along with Single IP management feature which incorporates virtual stacking over IPv4, IPv6 and IPv4/IPv6 dual mode. Employing DECT 6.0 technology, this phone offers virtually interference-free performance in any work or residential environment. The phone system is expandable up to 8 handsets, so adding an extra handset is quick and easy.