Some of you may know that "Shock Theater" test packs were sealed with either a black or purple ingredients sticker on the back. There was a discussion of this over on the vintage forum a year or so back. I now believe I have an explanation for this. Most of you may not know (I sure didn't until a few months ago) that there are two different pack configurations for "Shock Theater" test packs... 3 card packs and 7 card packs. Having recently obtained some of the 3 card packs, they were all sealed with the black ingredients sticker. While I don't own a 7 card pack, most all images I have of either packs or wrappers, seem to have the purple ingredients stickers. I believe Topps purposefully used the two different colors to distinguish between the two pack configurations. Topps almost always had a good reason for doing things that collectors scratch their head about today, and this is just another example. So you pack collectors may have a 'new' pack to go after.