Features : Highly efficient digital amplifier (Class D) produces maximum power. High-performance, custom-designed neodymium Micro Drivers deliver crystal clear sound. Revolutionary MaxxBass? technology creates deep bass without a subwoofer. Built-in docking station provides same synchronization and data transfer options as your iPod dock (cable not included) and allows you to recharge your iPod. Extra long battery life delivers up to 24 hours of continuous playback with four AA batteries (not included). Lightweight design folds to close at 15 ounces and 8 inches wide, 5.4 inches deep and 1.2 inches thick. Convenient auxiliary input jack for connection with other audio devices, including laptops, older iPods, and other MP3 players (3.5mm stereo cable included). Elegant, integrated power and volume controls. Headphone jack for private listening. Compatible with : iPod photo, iPod mini, 4th Generation iPod with Click Wheel, 3rd Generation iPod with touch wheel and buttons Specification: Input sensitivity: 500mV Output Power: 2W*2 8(OHM) 10% TDH Speaker: 1.25inch*4, 4(OHM) 3W, Iron frame and built-in speaker Function: Vol+ Vol- Control, Power, Switch AA Size Battery (not included) Out-link Power System Response: 60Hz -18KHz +/- 3dB Dimension: 205mm*138mm*30mm BOX Size:235*12*173mm