This Apple-branded adapter allowed a powered microphone with RCA inputs (red and white plugs) to be plugged into a Macintosh with a 3.5mm microphone jack.
The adapter features an Apple logo (on the RCA plug end) and Apple’s microphone icon (used in the 1990s) on the 3.5mm plug. The adapter is made in the platinum color used by Apple throughout the 1990s until the release of the iMac in 1998.