The Snom C520 - WiMi combined with the Snom C52-SP is the perfect solution for people who regularly hold teleconferences in large rooms or with large numbers of people. Up to three C52-SP units can be paired wirelessly with the Snom C520 - WiMi with ease, then serving as fully hands-free modules thanks to the two integrated microphones and powerful speaker. With Snom HD-Voice, voices are transmitted in crystal-clear quality through the high-quality speaker and integrated microphone. The integrated battery in the C52-SP enables talk time of up to 12 hours .