1LOSSLESS SIGNAL AND INTERFERENCE RESISTANT: This is a stereo switch box with lossless signal, solid aluminum alloy shell with strong interference resistance 2SMALL AND PORTABLE: Mini stereo audio preamplifier possess small size, easy to carry and use. Size is 88mm(L) x 38mm(W) x 38.5mm(H) 3RCA JACK 5MM OUTPUT: This fader input and output are stereo, usually used to control small signal controls, installed between the audio source and the preamp or between the preamp and the amplifier, strings in the audio loop. Outputs are 5mm or RCA jacks 4WIDELY COMPATIBLE WITH ALL AUDIO DEVICES: Fit DVDs, CDs, set top boxes, MP3s, TVs, cell phones, computers, tablets, turntables, sound cards, guitars, basses, electronic musical instruments, game consoles or other devices 5BETTER EQUAL SOUND CIRCUITWhen playing music at a low volume, feels that the treble is weak and dull, and the bass is small and weak. According to the characteristics of human hearing, the equal sound circuit increases the treble and bass at a low volume, making the sound range wider and better