Mini portable speaker fits all 3.5mm earphone jacks and is perfectly suited for use with your laptop, notebook, pc, mp3 player, pda, mp4 and so many more devices.  Uses 2 AAA batteries (not included).  Has an on/off switch and is easy to control and use. Comes with a chain to hang on your purse, bag or backpack when not in use.  Measures appx. 3" across at its widest point.