Fangrui Product Details Cordless Speaker Is Compatible With For 18v Li-ion Bl1830 Bl1840 Bl1850 Bl1860 Bl1860b Bl1870 Series Battery. Plug In Your Own Battery To Enjoy The Ultimate Stereo Sound! Low-voltage Protection Is Our First Concern. The Speaker Automatically Shut Down If The Battery Voltage Is Below 15.5v To Prevent Any Overload Damage. Portable Speaker Liberates Clear High Notes, Deep Bass And True Hd Sound Through The Built-in Speaker And Works Great With Smartphones, Cellphones, Tablet Pcs, Laptop And So On.there Are 7 Types Of Lighting Flashing Modes, Which Dance With The Music, And The Flashing Strobe Makes Music More Dynamic And Attractive. After Bluetooth Speaker Is Turned On, Short The Button To Switch Colorful Lights Double. The Bluetooth Speaker Support U Disk Play And Tf Card Play, Disconnect The Bluetooth Of The Stereo,and Play The Music On The U Disk/tf Card.(u Disk And Tf Card Not Included) Usb-a (dc 5v2.1a ) And Usb-c( 15w )ports Can Charger Low-power Mobile Devices. Low-voltage Battery Protection: If The