Features:Supports BT connection and TF card music playback modes, allowing you to enjoy music anytime and anywhere.BT 5.1, high data transmission speed, stable performance, and low power consumption, delivers great sound quality.Built-in 500mAh rechargeable battery offers continuous working time for about 4 hours.Mini size, with a portable lanyard, you can hang it on your backpack, or just put it in your bag.Supports true wireless stereo function, two of them can connect to each other for stereo and powerful rich sound.Full-color RGB light makes it cool on your way. Double click "-" button to turn it on and off.How to activate the True Wireless Stereo function:Activate true wireless stereo sound by pairing 2 BT513 speakers. Turn 2 speakers on and double press the power button of one speaker, then two of them will pair automatically.Specifications:BT Version: 5.1Operation Range: 10m (no obstacle)Horn: D52mmRated Power: 3WFrequency Response Range: 250Hz-16KHzSensitivity: 77±3dBBattery Capacity: 500mAhWorking Time: about 4 hours (Medium Volume)Charging Time: about 2 hoursTF Card Support: Max. 32GB (NOT Included)Charging Port: Micro USB, DC 5V 300mAColor: Pink, Blue, Green, Cyan (Optional)Item Size: 88.8*68.2*36mm/3.49*2.68*1.41inItem Weight: 105g/3.70ozPackage Size: 9.3*8.3*3.7cm/3.66*3.26*1.45inPackage Weight: 126g/4.44ozPackage List: 1 * BT Speaker1 * Audio Cable1 * User Manual (English/Chinese)