A bit of history about the Segal Lock and Hardware Company.
They manufactured locks and decided to go into the razor blade business. They designed a one-piece razor that took proprietory blades. It has a unique opening mechanism. It was patented and introduced in 1931. Two years later Gillette managed to get their patent declared invalid in 1933. That ruling was overtuned in 1939, not that it mattered. Their razor never took off and they were pretty much done selling razors and blades years before.
The same company still exists today and still manufacture locks.

The first image below shows the complete package down to the little manual and the cardboard blade. The tuck of blades is still sealed
The unique opening mechanism is shown in the middle image on the bottom row and the last image shows a suitably modified DE blade.

And for those of you that want to know how I modified the blade - I engraved the unwanted pieces out.