"The typewriter doesn't judge you. It just goes, 'Right away sir,'" Mayer says in the trailer. "'However you want it to be.'"
Hanks, who launched a free typewriter app for smartphones, is the owner of more than 250 different typewriters, 90 percent of which are in working order.
California Typewriter also features testimonials from historian David McCullough and playwright Sam Shepard about why the typewriter is still their go-to writing device. The film also focuses on the typewriter repairmen and artists creating artwork out of typewriter parts.
California Typewriter will hit select theaters on August 18th, with a iTunes release set for October.