Share a Single Stereo Source: 4 channel amplifier with separate volume knobs for each of the 4 outputs. No audio crackle, minimal distortion at highest volume Fantastic Stereo Audio Quality: Mini stereo amplifier with 4 x 1/4'' Stereo Headphone TRS Output Connector Jacks, 1 x 1/4'' TRS Source Input Connector Jack Compact and Portable: Solid metal build construction headphone mixer, tight connections, smooth operating knobs. Components and exceptionally rugged construction ensure long life Used for Applications: Features a durable and compact design headset amplifier perfect for both on-stage and in-studio performances or application that requires multiple headphone connections Headphone amplifier 4 channel would be excellent for up to four people monitoring the mix for tracking, live uses. Ultra-compact headphone amplifier system for studio and stage applications