These are paper indexes from maxell, designed to be used inside cassette cases. There are 3 sheets in each pack. The front features a sparkling foil-stamped design. There are two designs, shown in photos 1 and 3, and each pack has an advertisement for DAT tapes on the back (photos 2 and 4). I haven't opened the packs, so I haven't seen the back of the indexes, but I assume you can write recording details on them. Sorry if I'm wrong! I don't remember how I got these, but they might have been distributed during a DAT tape campaign. Is anyone interested? Please let me know.