These are quality genuine French barrettes and that is why they cost more. All stamped "made in France" They have only two parts to
them, the barrette back and the hinged clip. Chinese copies are often
sold as a "French clip" of "French style" but they will not have the "made in France"
stamp on them. You will find the Chinese version also have three
separate parts, they tend to break and are made of a weaker steel. The
measurement given is the length of the barrette back from end to end.
You can use these barrette backs to glue, solder or sew things on to. French auto-lock barrette backs are of Superior quality and meet EU Nickel directive. These have the smooth rivet holes as opposed to the pronged holes you sometimes see.