This Transfo brand lighter was made in France beginning in 1949. It uses its own unique brand of very long flints. The long, screw-tensioned plunger presses the flint against a very large file wheel that is contained in a compact chamber with a singular exit. This exit leads out of the lipped hole on the side in a conical shape.The folding brass key on the side is to be spun clockwise, which turns the file wheel against the flint and creates a large shower of sparks in the exit hole; enough to light up a cigarette or pipe! As the flint is ground down, the plunger can be telescopically pulled out and turned to add more tension to the now shortened stick of flint. The brass key can then be folded back so that its low-profile for carrying in ones pocket. The engraved acronym on the inside of the striking key, B.S.G.D.G. stands for Breveté Sans Garantie Du Gouvernement ; French for Patented Without Government Guarantee.
We currently have a life-long collection of lighters dating from the 1930's to the 1970's for sale. The condition of these lighters varies from fair to very good. I have photographed and described them as accurately as possible and I do mention obvious faults in the description.
Kindly note that I am no expert so please study the images above and descriptions carefully to assess condition, completeness and authenticity. The lighters are sold as untested and as is.