I've been on the hunt for a shirt like this for longer than I care to remember. Time to check it off the list!
My new 1950's era Montgomery Ward Powr House workshirt. Features include MW Gripper snaps, double fabric back, shoulders & elbows, 16 ventilation eyelets at back & underarms and point of strain bar-tacks in green cotton thread, Vat-Dyed dark blue chambray, triple stitch seams with bar-tacks, interlined collar. Nice!