MT-S28 ,Notebook 2.0CH Speaker USB Power supply . CE/Rohs MOQ: 3000pcs ♦ ... , etc.♦ Green materials, environmental protection and energy savingPower: USB DC5V THD+N (Amplifier): <=0.2%Input sensitivity: ... 4ohmSignal to noise ratio (Amplifier): >=95dBAConnect by USB and audio, For PC ,notebook ,MP3... *Built in low-frequency reactive ... *N.W.:0.475 KG (Around) Notebook 2.0CH Speaker USB Power supply