Specification: Product model: C28 Bluetooth audio receiving and transmitting combo Product color: black Battery capacity: 140Amh Working range: 10m (without any obstacles) Charging time: 1h Use time: 4h Interface: AUX Whether plug and play: plug and play External power supply: No external power supply Transmission rate: 5 (Mbps) Effective working radius: 10 (m) Bluetooth standard: 5.0 Working frequency: 2.4 (MHz) Suitable type: computer, TV, projector (transmission mode)/speaker, earphone (reception mode)