Mini Portable Hamburger Speaker Amplifier for iPod iPad Laptop iPhone Tablet PC (Black) Size: 50mm (W) x 50mm (L) x 35mm (H)/1.97'' (W) x 1.97''(L) x 1.38''(W) (Approx.) Socket Size: 3.5mm 360-degree sound field intergrates a cone design with a custom-built speaker to project sound in all directions. With 1.4 subwoofer, the vacuum base offers deep and rich sound with HI-FI result. Built in, rechargeable lithium battery each charge can last for 3 - 5 hours.