Aiptek Fidelity Mist Portable Speaker for MP3 Players (Gray) Ultra-compact portable speaker for MP3 players, iPods, and other audio devices Fits above audio player's 3.5 mm headphone jack for maximum convenience Pair of 0.78-inch full-range drivers deliver 150 Hz to 20 kHz frequency range Runs for up to 8 hours on 2 AAA batteries (not included); 2-step volume control Measures 2.44 x 2.44 x 0.63 inches (W x H x D) and weighs 1.48 ounces