Maxhub BM21 has Built-in high-performance large dynamic speakers, with intelligent noise reduction and echo cancellation algorithms, and PZM structure design bring you high-quality voice experience that supports 360-degree omnidirectional audio pickup to receive the voice from every seat in a meeting room. Connect via Bluetooth, a USB cable, or an audio cable. Connects to 3 devices at the same time. With 8-hour of playtime on a single charge.