I haven't heard that term for years. A multi-card reader. That was the input device for a computer. On one machine you typed in the info and it punched little rectangular holes into envelope-sized punchcards. Like, the name and address of a customer, one customer per punchcard. When done, you had a big stack of cards, like a couple of feet high, and you put them into the multi-card reader. It shone a light beam through the holes of each card and recorded the info into the hard drive (I don't think there were floppies yet). I used to use these for class homework in computer labs at a couple of different colleges in 1969-75. By the late 70s, I don't remember seeing them. By then or the early 80s, I think the keyboard was wired directly into the computer.
As for what that colorful plastic thing is in the picture, I have no need to learn.
