... doing exercise,Line-in function,work as extra speaker for laptop, etc. Key Features:• Play Mp3 WMA music• Flash Built-in 1G to 8GB ... Optional)• Support TF Card • Line-in function, work as extra speaker for other digital device ... , Mp4 player, etc. • FM function included• Built-in lithium battery, working 10 hours • High quality speaker: 1.5W X 2 • Can fix on ...