POLY Sync 40+ USB-A USB-C Speakerphone +BT700 USB-A Adapter. Device type: Mobile phone/PC, Product colour: Black, Silver, Signal-to-Noise Ratio (SNR): 55 dB. Driver type: Dynamic. Microphone frequency: 100 - 6700 Hz, Microphone direction type: Bidirectional microphone, Microphone sensitivity: -45 dB. Connectivity technology: Wired & Wireless, Interface: USB/Bluetooth, Bluetooth profiles: A2DP, AVRCP, HFP, HSP. Power source type: Battery, Battery technology: Lithium-Ion (Li-Ion), Talk time: 30 h