The TS30 butt set is designed with all the reliability and durability you expect from Fluke Networks. The TS30 offers high-impedance monitor for DataSafe operation, along with features for enhanced comfort and unsurpassed RainSafe protection in extreme weather conditions. With its built-in DataSafe features you can clip onto a line in monitor mode and the high impedance monitor will prevent disruption of data transmission on the line. The contoured handset offers special purpose keys, including a mute key that cuts off noise from the microphone and a hook flash key for retrieving call waiting or transferring a call via Centex. The TS30 also features a circuit that adjusts speech levels automatically, so you'll always be heard loud and clear. There is an audible electronic ringer, a hearing-aid compatible receiver, and selectable tone or pulse dialing. Warranty 18 months.