Hi everyone, I'm looking for a product, I searched online for it, but I don't know what it's called, and so my searches found nothing. I'm looking for plastic 3-ring binder sheets that hold index cards in slots. In other words, there would be an 8.5 x 11 inch sheet of plastic that has 3-ring binder holes on the left side, and this plastic sheet would have 4 slots that you can slip index cards into. Ideally it would have 4 slots on both sides of the sheet. This product is too obvious and too useful to not already exist. Please, if you know of a product like this, please help me find it ASAP! I really need it as soon as possible. Thanks so much!