Compact mini speaker is 5.2 cm(2.05 inches) in diameter, it can travel with you anywhere. Compatible with most devices that may utilize headphones. 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 6 - 8 hours. Magnetic shielding allows for placement next to computer monitors without causing interference. Pioneering patented technology: extendable resonance of the bass box technology enables stronger effect. Standard 3.5mmaudio plug, apply with all music player and digital products. New concept integrative portable mini speaker, with small bulk can play on the center of the palm. Using high-fidelity loudspeakers, the all exported more chear, the bass more pure & stronger. Embedded type lithium batteries, can use USB or power adapter for charging. More convenient and user-friendly, cost-saving pruphase batteries.