Grandstream GSC3510, 3 microphones, Speaker (8W), Wired, Wireless, Wireless 802.11a/b/g/n, Bluetooth, 10/100 Ethernet, PoE+, LAN/power, White, SIP compliant, 2-way audio, Built-in 3 microphones, Built-in speaker (8W). This robust SIP intercom device offers 2-way voice functionality with both a high-fidelity 8W HD speaker and 3 directional microphones with Multichannel Microphone Array Design (MMAD) that offer a 4.2 meter pickup distance.