Pyle Home PHE1AB iPod and iPhone Headphone Amplifier Designed for iPod/iPhone, Improves the sound quality with the line out from the dock - Easy & simple to use, plug and play - Distortion: &lt;0.009% (10mW) - AMP dock: 33.8mmx30.8mmx7.8mm Build in high quality Texas Instruments's headphone amplifier Integrated Circuit - Powered by the iPod/iPhone (no charging or battery needed) - Frequency Response: 10Hz ~ 80KHz - Length: 800mm(Line Exposed) High power output to drive high impedance or low sensitivity headphones or earphones - With a built-in clip, you can clip it onto anything - Suitable Headphone Impedance: 16 ohms ~ 300 ohms - Weight: 20g Easy control of the playback of the iPod/iPhone while the player stays securely in your pocket - Output Power: 100mW (16 ohms Loaded), 12mW (300 ohms Loaded) - Power Supply: Use iPod/iPhone power 3.3V Compatible with iPod Nano, iPod Video, iPod Touch, iPhone, all generations & all versions - Signal to Noise Ratio: =98dB (A weight) - Line control dimensions: 48mmx14mmx10.7mm