Panasonic KX-TG6583T DECT 6.0 PLUS Link-to-Cell Bluetooth Convergence Solution with 3 Handsets + Two KX-TGA651B Add On Handsets = Total of 5 Handsets DECT 6.0+ Technology Up to 4-way Conference Calling Talk Time: Up to 13 hours Standby Time: Up to 11 days Expandable Up To Six Handsets