Karnotech REMAX Portable Wireless Bluetooth Speaker Mini Sports Audio Player Powerful Sound with Build-in Mic for TF card iPhone iPad iPod Samsung Tablet Laptop MP3 RB-X2 Red Mini size, big sound! Connection: Bluetooth & TF card High-capacity polymer battery, 5 h continuous work time. Bluetooth hands-free calling features, enjoy complete freedom. Works with smartphones, tablets and other players with Bluetooth wireless technology. HD stereo, large caliber passive radiator, excellent sound quality, enjoy music anytime & anywhere.