The adapter enables the use of an Atari, Nintendo (NES), Super Nintendo (SNES), Sega Genesis (three- or six-button), or Sony PlayStation 1 or 2 controller with an Apple II, II Plus, IIe, IIc, or IIGS. This is the second revision of the card in 2023, which adds support for the Apple II and II Plus.
The adapter costs US$54.95 plus shipping and comes with a D9 extension cable. More information is available in the product wiki. As stated, supplies are limited!