Aluratek's Bump 3.5mm Portable Mini Speaker with a built-in Lithium-ion battery packs quite a punch for a little guy. The APS01F Bump was designed to add high quality audio to your smartphone, MP3 player, tablet, or any other device that has a 3.5mm headphone connector. Simply plug the built in 3.5mm audio connector to your device and switch the power on. That's all you need to do to start "bumping" to your favorite music. You will enjoy up to 8 hours of continuous use via the built-in rechargeable Lithium-ion battery which easily connects to any USB charging port and includes the USB charging cable. The Aluratek Bump features an expandable bass chamber to help add more bass to the music from your smartphone or tablet. Press down on the base of the speaker to release the extension base, and the base will pop up, creating more space for bass to resonate. Then simply connect with MP3 players, mobile phones, portable CD players, laptops and tablets, or any audio or mobile device with a 3.5mm auxiliary audio output and start "bumping" to your favorite music.