Professionally inspected and serviced, calibrated to factory spec. Tested and 100% functional, no significant cosmetic issues. The best selling classic MidiStudio 644 mixer/cassette recorder from TEAC/Tascam, the most dependable name in home recording. Professionally inspected, serviced and restored to factory spec, functioning perfectly. Includes AC power supply. Ships worldwide.

From the owner's manual:
"...The 644 MidiStudio is a 4-channel multitrack cassette recorder,  a 16 input mixing system with electronic routing control, and a MIDI
Tape Synchronizer combined into a single workstation. Each main  channel can access up to 4 effects busses, so you can use a variety of
different effects on different inputs. MIDI Tape Synchronization with  Song Position Pointer (same as that used by the TASCAM MTS-30) is
built in, so that the capabilities of MIDI sequencing can be blended with the advantages of multitrack recording..."