Callers can speak and be heard at the same time, just as they would in a face-to-face meeting. Pair up to three VCS850 DECT Expansion Wireless Speakerphones to increase the volume and microphone pickup for 27 or more active participants. With G.722 wideband codec support for HD audio, calls have never sounded so rich and life-like. With 12 hours of talk time, you have plenty of room to keep the meeting going on one charge. With up to 70 hours of standby time, there's no need to worry about losing a charge mid-meeting. Enjoy the peace of mind that comes with an industry-leading, standard two-year warranty.