The Shure A95P allows a low-impedance mic to work with a high-impedance input, such as a guitar amp.
The 274 017 allows a high-impedance source (such as an electric guitar) to input a low-impedance mic input, similar to what is found in most modern PA mixers, like a direct box.
Shure A95P Low Hi-Z Impedance Microphone Line Matching Transformer.
A95P is used to couple a high-impedance microphone line to a low-impedance amplifier.
Equipped at the high-impedance end with in-line phone jacks, which are compatible with microphone plugs and provide a quick and easy connection.
Model A95 Series Transformers are supplied wired for a 150-250 ohm microphone rating impedance.