I think you'll have to post a picture of it for folk to identify what you have.
Such a thing was soon forgotten and recycled because I found that formatting diskettes was all I needed.
First, this question is not as specific as I would like. This question is about a thing I used to use to reset floppies and memory back to its original state. This was a thing about 6" long, 2/3" wide and 3/4" high. It plugged in and it had a little button on it. When the button was pressed it hummed a bit and also vibrated. I think it sent out some kind of magnetic field. When one was done the item was restored to its original condition.
My problem is that I can't remember what the thing was called and it was 30 or 40 years ago. I was wondering it this thing, if I could figure out what it was, would work on sd cards today. If anybody could remember what it was I would really like to know. Again, I apologize for the sketchiness of this.