Kocaso Mini Portable Bluetooth Speaker With Bass Xpansion System And Rechargeable Battery Wireless Speaker (Gold) Powerful and clear sound in unique design it has BXS (Bass Xpansion System) to deliver a fuller, richer low end response. Compatible with Bluetooth phones, MP3/MP4/Tablet/Laptop/PSP Support A2DP, AVRCP, headset, hand-free profile. TF/Micro SD card support. Built-in Rechargeable Li-ion battery.