For context: Cliff, who designs and sells these bottles, is also the guy who busted KGB hacker Markus Hess in the 80s.

EDIT: I just found out that he also offer the Imperfecto Rulers from Theophilus Measure Co[1]. The accompanying video [2] made my day.

[1] https://www.kleinbottle.com/imperfecto

[2] https://www.youtube.com/watch?v=9yUZTTLpDtk&