The Primoflex Automats (1956-7), were a major departure, introducing a fully automatic
shutter-cocking model with crank wind. The initial Automat was superseded by the Automat L
in 1957. The Automat L was the last Primoflex, and differs from its predecessor mainly in the
shutter (MXL version), fitment of an accessory shoe (integrated into the left-side strap hanger),
style of shutter lock, and the use of EV settings on the shutter (with exposure explanations
circling the crank axle on the right side).

In the pictures below, the Automat is always on the left, the "L" on the right. Notice also the
change in the logo style between the two models. "To Ko" is, I assume, an abbreviation for
"Tokyo Kogaku".