This ingenious design, patented in 1921, folds up to only slightly bigger than a double edge blade. The top cap and base plate are hinged together; place a standard DE blade between them and clamp it shut. Rather than a standard handle, you fold out two wings and hold them with your thumb and forefinger. The star-shaped holes make it easy to grip.
A fascinating curiosity for your collection, but also bperfectly usable as a travel razor that will take up very little room in your dopp bag.