The Sennheiser MD 421 was released in 1960 to much acclaim, with a very tight cardioid polar pattern that borders on "supercardioid" at many frequencies and a clear, present sound that was far superior to most dynamic mics of the era.

The MD 421-2 model features a large Tuchel connector with flat pins and is without the M-S "music-to-speech" high-pass filter switch.