ClearOne Max EX 910-158-500 Wired Expandable Conference Phone (Refurbished)Key Features: Mfr. Part #: 910 158 500 ClearOne Max EX Wired Expandable Conference Phone Single unit conference phone Full Duplex sound enables participants to speak and listen at the same time without cutting in and out Expandable up to 4 Max EX Phones Customizable room configurations with multiple phones Noise cancellation removes background noises from fans Automatic level controls keep participants audio balanced and consistent First Mic Priority