mid century machine age steel slide cases, hammered industrial paint

Lot of 1950s vintage steel slide storage cases. Each case holds 150 2" (usually 35 mm) slides. The paper index cards in the lids are yellowed, but have never been writen on.

They measure about 14 1/2" x 7 3/4" x 2 1/4". One is marked Brumberger and the other is unmarked.