--FM radio frequency: 87.5~108MHz. --Powered by built-in rechargeable lithium battery for durable to use. --Adopts anti-magnetic aluminum vibrating diaphragm mini speaker with clear sound quality, to let you indulge in your favorite music. --Support to play MP3 music from your Micro SD/TF or U-disk, plug and play. --Multi-color LED flashing light at the base of the speaker, very cool. Features - Color: Blue. - Material: Aluminum Alloy. - Size: Approx. 50 x 48 x 52MM. - Adopts anti-magnetic Aluminum vibrating diaphragm Mini speaker with clear Sound quality, to let you Indulge in your Favorite music. - Support To play MP3 music from Your Micro SD/TF or U-disk, Plug and play. - 3.5mm Audio input: the speaker Can also be connected with Your 3.5mm-jack audio devices, Such as iPhone, iPod, Tablet PC, MP3, MP4, Etc., to let you Enjoy wonderful music. - FM Radio: With built-in Radio frequency module And telescopic antenna, it Can be used to listen To FM radio. ( Support Auto search ). Specifications: - Battery Type: built-in 600mAh Rechargeable lithium-ion battery. - Input Voltage: USB DC 5V. - Playing time: About 2-5 hours after Full charge. ( The actual Playing time depends On the music Volume size ). - Music format: Support MP3 Format. - Output Power: RMS 3Wx2 tHD=10%. - Frequency Response: 150-18000hz ( 3dB ). - Signal And noise ratio: More than or equal To 85dB. - Main Interfaces: 1 * Micro SD/TF Slot, 1 * USB 2.0 Port, 1 * mini USB power Port, 1 * 3.5mm Audio input, 1 * 3.5mm Audio output.