These are 6" by 9" mystery investigation cards printed on cardstock for your mystery party. Each player - whether in a character role, an expandable team, or a spectator - should all have one of these during the game to take notes for the investigation. There is a section for them to write their best guess of 'whodunit' and then, they turn in this card to the host.
It wouldn't hurt to have a few extra in case your players want one. All party packs (boxed sets) come with one card per player. Purchase these if you are having spectators, or if you are preparing your own kit (the download), or if you just want to have some extra.
The standard option is 10 cards. If you need more, choose the size in the drop down box that you need. For more than 100, put more of this product in your cart and choose the appropriate quantity.