This is a sheet of water-slide or dry transfer decals for marking aircraft models.
A set of precut self-adhesive vinyl appliques to represent the stiffening plates applied to F-16s. The set covers USAF and NATO aircraft from blocks 25, 30, 40, and 42. Instructions are given for each user and block type to show you exactly which stiffener is needed, and where. Enough for one 1/48-scale Tamiya model.