Patented in 1965, the Meiwa 'Alexe' was one of the final evolutions of the affordable compact mechanical pocket adding machines before the advent of electronic pocket calculators. Capable of calculating up to five figures, it featured a clever addition-subtraction shift mechanism and quick-clearing mechanism. 

SOURCES

https://patents.google.com/patent/US3312395

https://www.jaapsch.net/mechcalc/alexe.htm

https://www.rechnerlexikon.de/en/artikel/Meiwa_Alexe

https://www.retrocalculators.com/Ricoh-Alexe.htm