This is a copy of an ad that appeared in the 1948 French Bicycle Trade Directory, "Botin du Cycle. It is advertising a set of lugs (the red tube jointing sockets) to be used in constructing a "mixte" - a step through frame. Nervex was the dominate manufacturer of the pressed steel lugs that ruled the bicycle industry. They were made of two pieces of pressed steel welded together. The lug was rough, particularily the joint, and they required a lot of hand filing. Investment cast lugs came out and Nervez and pressed steel were history. Of course time moved on and now any lug is rare except on custom high end steel bikes.
When Velo Orange decided to sell bicycle frames, Lorna's mixte was a prototype, and when the smoke cleared I ended up with a couple of mixte lugs in a bottom drawer. Now years later I purchased an old man's bike, a manly sized Ron Cooper mixte, and it's interesting to see the raw lugs compared to a finished bike.