The Calrad 4 Channel Stereo Headphone Amplifier is perfect for use in recording studio or educational applications. Works directly with 1/4” TRS phone jacks using 8-100 ohm impedance stereo headphones. Each channel uses Texas Instruments RC4580 Ultra low-noise series op amps that deliver outstanding audio performance with low distortion. Provides stereo audio for individual or multi-person listening environments. Each channel can be adjusted independently with individual volume controls.