Model T-2020 Type Portable Colors Black + Silver Quantity 1 Material Aluminum alloy Internal Memory No Memory Card Type USB flash drive / TF card Max Extended Capacity 16GB Media Format MP3 Total Power 3W Impedance 32ohm Signal to Noise Ratio(SNR) >=70dB Sensitivity 150~18000Hz (+/-3dB) Channels 2 Remote Type N/A Interface 1 x TF card slot 1 x USB 2.0 port 1 x 3.5mm jack 1 x Mini USB port Power Supply Built-in Rechargeable Battery Built-in Battery 300mAh Other Features There is blue light when power on Packing List 1 x Speaker 1 x Data cable (48cm)