Philips 4000 series TAH4205BK/00. Product type Headset. Wearing style Head-band. Recommended usage Calls/Music. Connectivity technology Wireless. USB connector USB Type-C. Bluetooth profiles A2DP.AVRCP.HFP.HSP. Ear coupling Supraaural. Acoustic system Closed. Headphone frequency 20 - 20000 Hz. Microphone type Built-in. Battery type Built-in battery. Battery technology Lithium Polymer (LiPo). Continuous audio playback time 29 h