*【Share a Single Stereo Source】Amplifier 4 channel with separate volume knob for each of up to four outputs: No audio crackle,minimal distortion at highest volumes.No loss of signal when all four headphones are connected.Headphone amplifier 4 channel would be excellent for up to four people monitoring the mix for tracking,live uses and listen to the TV with earbuds while working out. *【Fantastic Stereo Audio Quality】Mini stereo amplifier with 4X 1/4'' Stereo Headphone TRS Output Connector Jacks,1/4'' TRS Source Input Connector Jack.◆Stereo ◆:You must use the 1/4" TRS stereo audio cable male to male connectors for input and output connection.◆Mono◆: 1/4" TS male to male connectors for input and output connection.■■TRS/TS cable is not included in package■■ *【Compact and Portable】Solid metal build construction headphone mixer, tight connections, smoothly operating knobs.High-quality components and exceptionally rugged construction ensure long life.Ultra-compact headphone amplifier system for studio and stage applications *【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.Convenience to use if two or more audio setups on your computer or using stereo amplifier to listen to music or watch TV works great. *【What You Get】--Ultra low noise headphone amplifier provides you outstanding audio performance. 12V DC power adapter included, with light for indicating power on.1 Year Warranty for FIFINE Headphone amplifier. if you have questions, please contact us directly to get the service