This is the very rare 60 MHz triple trace oscilloscope with it's matching Time-Voltage module. This is a close copy of Tektronix 465B with the DM-44 option.  The 465B is a 100MHz while the Heathkit is a 60 MHz. I sold my unit and bought a 465B with a DM-44. The Heathkit never had the reliability and stability of the Tektronix. If you are collector that is good but buy a 465B if you want reliability and accuracy.