This is an audio splitter and amplifer. You can connect one sound source to the input and then 4 audio output, which you can control the volume of the individual output channels. It is useful when you want to connect multiple headphones or speakers to it and control wach speaker or headphone volume separately. It's well and strongly built with quality sound in mind. All ports, including the input and the otuputs, are 1/4 inche 6.5mm Jack.