Nowadays lots of live reinforcements and multimedia teaching need laptop to play music. The laptop outputs signal to mixer via unbalanced cable which has bad anti-interference capabliity. VGA cable connecting laptop and projector interfers the signal. The voltage differences between connected equipments lead to AC noise to wores the listening effect. This is a big headache for audio engineers. In the vehicle application, when 3.5mm AUX connector and onboard charger are used simultaneously.The audio system generates AC noise. Soundking studies and tests for many times and uses isolation transformer of new material and technology to isolate the voltage difference between two systems to prevent form the equipment inputs damaged and eliminate the noise caused by sanme ground and achieve better signal transmission. This product is convenient to connect and is the essential product for audio engineers. Connectors: 2 x Mono RCA / 2 x Mono RCA.