Like typewriters, check protectors are single purpose machines. A check protector embosses the paper check with the dollar amount and indelible ink then perforates the paper making fraud difficult. This is an older model that uses an ink roller to apply the ink. Modern machines use a wide ribbon.
The ink is quite gooey and will stain ANYTHING. I was washing my hands after servicing this little guy, looked in the mirror and I had a red smudge on my forehead. Later in the day I looked down and I had a red mark on my shoe!