... Lithium battery, keep working with 8 hoursOuput power: 12 W, clear and nice loud voice, good penetration.Aluminium magnesium alloy material ... 8 hours Recharger DC7.4 V/ 2000 mA Battery working time Keep working in 7-8 hours Function ... -in, loudspeaker, microphone, reverberationColor ChoiceBlackWeight 0.5kg ( including battery )Size128*50*85mmApplication:Used for Yoga, Gymnastics,Teaching, Conference, ...