Power Mac G4 - AirPort card too big for slot

I have an old Power Mac G4, for which I acquired an AirPort card, and tried to follow these simple instructions from YouTube but it turns out that the card does not physically fit into the slot. It's too wide. I've attached 3 photos to show the comparative width of the card and the slot, and the nature of the slot it needs to fit into. As you can see, it's quite different from the hardware shown in the video tutorial. What I'd like to know, is what kind or model of AirPort card does this Mac take? I assumed it was the type shown in the photos, but that's obviously wrong.