USB Speaker 1.For PC,MP3,MP4,Mobile Phone and notebook 2. Built-in ative amplifier 3.small sized design,easy to take Laptop SpeakerSpecification Impedance: 4Ω Power output:2.5W Power consumption:3W SNR:≥85db size:85(L) X73(H) X89(W)mmBox size:18.5*10*9cm40pairs/Carton Outer carton:52*39*38cm