The all new BT HD is the newest model in the family. It connects using the latest Bluetooth version to a SINGLE cell phone. All audio connections are wideband 16kHz audio for the best possible sound. The makes it possible to make and answer cell phone calls using regular home telephones. No more searching for your cell phones, just use regular telephones at home or in the office. No more paying for a landline – just use your cell phone plan. Ditch your land line service without losing the use of your corded or cordless phone systems at home or in your office. All calls are placed using your cell phone's plan. No new number or contract is necessary. The BT HD works with existing wired and wireless phones. No new equipment is needed. Many homes and offices have dead spots. The BT HD allows you to keep your cell phone in a location with good reception. Calls can then be made from anywhere in the home on your existing home phone equipment. The BT HD connects to ONE cell phone. Fully supports antique and rotary dial telephones. The BT2 and BT HD have the highest ringing power output and can ring multiple antique telephones. Product Contents: - BT HD, Power Adapter, User Guide CONVENIENCE - Use home telephones to make and answer cell phone calls WIDE BAND AUDIO - 16KHz Audio for the clearest quality sound WIRELESS - When cell phone is within Bluetooth range, connects automatically BLUETOOTH VERSION 5 PULSE / ROTARY - Fully supports antique telephones