KX-TGDA99S Cordless Telephone Handset works with KX-TGD89/ KX-TGF89 Series landline phones (sold separately) to expand your home phone system; DOES NOT WORK ON ITS OWN; MUST BE PAIRED WITH A COMPATIBLE PHONE SYSTEM. Pair up to 4 Bluetooth headphones, earbuds, or lightweight headsets to take calls or meetings hands-free and multitask, relax, or move easily around the home.