- New directional pattern: Open Cardioid
- Optimal combination of directionality (MK 4 cardioid) and warm sound characteristics (MK 21 wide cardioid)
- Natural sound quality, due to highly consistent polar diagram across the frequency range
- Popular for use as a spot or soloist's microphone, as the mid microphone for M/S, or as a main microphone pair e.g. at a spacing of 21 cm, angle +/- 55°