See-Through is a transparency spray that you can use to inspect the contents of closed envelopes or paper wrapped packages without opening or damaging them, and without leaving any marks. It is ideal for inspecting suspect envelopes and packages in your Business, Office or Home. Foreign matter, such as a powder, will be seen as a darkened area in the envelope. See-Through is a clear, non-conductive liquid that when sprayed on a suspect envelope or document will allow the user to clearly see the contents. After the document or envelope is dry (it dries in minutes), See-Through will not leave any traces or watermarks. Nor does it cause inks to run.