D & K Exclusives&reg; Bluetooth Speakers Mini Portable Speaker /Powerful Loud and Clear Sound with Bass / Built In Micro SD Card reader / Built in Mic. For Phone Calls / Works With All iPhones / iPhone 5c And 5s / All iPad's / iPad Air And iPad Mini Retina / iTouch and iPod / Nexus / Samsung Glalxy Note And Tab / Samsung Galaxy S4 S3 S2 / And All Phones and MP3 Players. Speaker System Has Built In Rechargeable Battery (PURPLE) USB Cable and 3.5mm Cable included to connect your device to the speaker. Features surprisingly loud volume range with bass feature. Frequency Response: 280Hz-18KHz. D & K Exclusives speaker has a slot for SD cards. Carrying case included. Output Power: 3.0W Built in battery with USB charging cable 5 hour battery life. Built in Mic allows you to use the speaker for phone calls as well Sometimes there is a very low and subtle steady noise coming out of the speaker. Thats a electromagnetic-acoustic sound from the speaker. This is normal with most speakers. When you turn the speaker on, if you press " play/pause " button, it will mute the noise.