The SB67128 Repeater extends the range of cordless extensions--up to a half a mile. The speakerphone base supports up to six repeaters, without any need for a wired connection. Just plug them into an AC outlet and get ready to roam. Active calls are handed off from base to repeater to repeater while you take care of business. All repeaters work with the AT&T TL7600 Cordless Headset for hands-free mobility.