EPOS EXPAND 20. Device type: Universal, Product colour: Black, Silver, Optimized for: UC, Skype for Business. Frequency range: 150 - 15000 Hz. Microphone frequency: 150 - 6800 Hz, Microphone direction type: Omnidirectional. Connectivity technology: Wired, USB connector type: USB Type-A, USB connector gender: Male. Talk time: 20 h, Standby time: 30 h, Battery recharge time: 2.5 h