You are looking at a desirable older used Amphenol male 4 pin microphone cable connectors from the 1950's - 70's. You'll see in pic # 2 this very connector type in an old Amphenol catalog. These connectors are a universal 4 pin with a notch so it can be used on Shure, Ampex, Electro Voice, Executone and other variant model mics.
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