For security reasons, tabulating machines print out something called a “zero tape”. In the case of election day voting, this tape is printed as part of the poll opening procedure. For other types of voting it’s printed before the tabulation process starts.

A zero tape is printed to prove that all of the vote total fields on the tabulating machine in question are indeed zero—that is, that the machine doesn’t “already have votes stored on it” from previous elections before the tabulation process begins for the current election. If a zero tape has any non-zero vote totals on it, it tells election workers that the tabulating machine needs to be reinitialized. Here’s an example of what the zero tape from the Crow County tabulating machine above could look like when it was printed in the morning before the polls opened: