M 221 B series
Eight interchangeable capsule types were offered, including a single-diaphragm, three-pattern capsule (MK 26) and the world's first single-diaphragm hypercardioid condenser (MK 241); the most widely-sold type was the two-pattern M 934 B (later the M 934 C or MK 25). The output transformers were wound by SCHOEPS and carefully measured and selected for lowest distortion.