NIZHI TT6 Outdoor Exercrise Mini Portable Speaker for MP3 with Micro SD card reader and radio function This Speaker not only for outdoor sports ,but also for exercise bike ,mountain climbing and outdoor picnic . Also suitable for home / notebook speaker / Kids study speaker/ exercise speakers /fetal education speaker. Optional laptop speakers primarily for convenient carrying, this sound box is a metal shell of the speakers, voice stress treble clear bass full. Outdoor audio / exercise speaker / bike audio / mountain bike audio. Seven cycle modes : normal mode, single mode, directory play, directory cycle, all cycle, random play to play