TuneBOOST In-line Mini Headphone Amplifier for Headphones , Earbuds , and Headsets for Beats By Dr. Dre , Bose , Sony and Much More! ** Includes Microfiber Cloth and Accessory Bag! ** Boosts the volume of any standard 3.5mm headphones or earbuds Provides up to 20 hours of off one replaceable AAA battery (not included) Easy-to-Use design, just plug in the cables and you are ready to go! Compact size fits easily in your pocket and weighs less than one ounce with battery Wide 10Hz-40KHz frequency response is perfect for any type of audio