70 hours long battery life: Built-in Lithium ion polymer 420mAh battery. Up to 70 hours playback, fully charged within 2-3 hours by USB charging cable. Enjoy your wonderful musical journey. Large memory capacity: Supports up to 128GB Micro SD Card. Lightweight and portable: Palm size and lightweight, easy to put into your wallet, pocket, or armband. Easy to carry, especially when you exercise, run, jog, travel, or hike. Perfect companion for your sports. Slim design, easy to use: A02S Music Player designed with classic buttons and simple navigation. Also a great audio player for kids. Download is easy—just drag and drop the music file or folder directly when connecting to computer. Works perfectly with car via AUX port. Lossless sound quality: Supports formats MP3, WMA, OGG, WAV, APE, FLAC, AAC-LC, ACELP. (Requirements for APE and FLAC: 8KHz-48KHz, 1000Kbps). Note: It does not directly support audiobook and iTunes. Brings you an amazing listening experience.