Tube Integrated AMP Power Amplifier Headphone Replaceable Basic Meter (Black). This amplifier can be used with KT88 or EL34 vacuum tube, and there is a Red selection button on the Back of the amp to switch. The default matching tubes of this machine is KT88. Pure hand-made, the whole machine is welded with scaffolding. Can be used as an Integrated amplifier, power amplifier or Headphone amplifier.Triode and ultra-linear selection are available, which can be switched by the button on the amplifier. With a remote control, Vacuum tube protective cover, Fuse and an English manual.