The X5 is made of high grade stainless steel. The X5 has a patent for a low frequency resonance system, which gives an extraordinary bass effect.Bluetooth version 4.0X5 supports more than 10 different kinds of music formats.Supports FM functionNFC functionFeature:(1) Can play music with connection to mobile phone, MP3, MP4, PC, IPOD and other devices if the equipment has a 3.5 mm socket(2) Suitable as a gift. Pocket size. Easy to take with you.(3) Charging indicator(4) Blue tooth connection to PC, Mobile, IPOD and so on(5) Microphone function(6) Support TF card function(7) Supports FM function(8) NFCTechnic specificationworking voltage: 7.4Vcharging voltage: USB 5V 600mAFrequency:         40Hz——18KHzSpeaker Unit:    52mm  4? 5WDistortion:           <=0.5%Case Material:   Metal+ABSDimensions:       77*77*62mmWeight:                               400gAccessories: Manual: 1pc                   Charging cable: 1pc                   Audio cable: 1 pc