The Siemens Gigaset Dune CL540H: A stylish GAP compatible additional handset The Gigaset CL540H is the correct additional handset for the Gigaset Dune CL540/A Cordless Phones. Features include: a brilliantly large TFT full-colour display, aone-touch loudspeaker, & integrated phonebook. Excellent sound The handset benefits from HSP & HDSP sound protocols, the sound quality of conversations on the Gigaset Dune CL540H is assured, even whilst using the speakerphone. Easy set-up You will have the Gigaset Dune CL540H set-up in no time with the fuss-free procedure for registration, enabling you to take advantages of an extra handset straight away: call transfer, intercom, shared phonebook, & more.