The MFAV metro cars are articulated, 8-axle rail motor coaches with an unusual 2'Bo'Bo'2'tr axle arrangement.

The MFAV designation resolves to Millenniumi Földalatti Vasút ("Millennial Underground Railway"), FAV and MillFAV refers to the same phrase, as the cars were specifically designed to replace the original, turn-of-century Schlick–Siemens & Halske rolling stock of Budapest's M1 metro line, a tunnel system which requires low-height vehicles.

The series carries the distinction of being an early example of fully low-floor urban rail vehicles.

The MFAV cars are based on the CSMG tramcars, but the geometrical constraints of the M1 metro line forced Ganz to modify the existing design in unique ways, such as moving the electric subsystems into the articulations between the body sections to achieve fully low-floor vehicles.

Eventually MFAV metro cars were produced in two production runs, these are shown in the following table.