Other transformers were also available to match medium and high impedance microphones to low impedance inputs, and so on. But the Low-to-High is by far the most common.
Here is a scanned manual for the Reslosound LTU1 line matching unit, which was used to connect 15Ω to 50Ω ribbon microphones to a high impedance tape deck. This was superseded by the LMT, which is essentially the same thing in a smarter metal can.
|Reslo impedance matching transformer.|