My 1957 Peugeot has a Simplex JUY 543 and in it's day this and it's brethren gave Campagnolo a run for the money... it shifts so well one would think it was indexed. It can be set to run 3, 4, or 5 speeds and is a low normal derailleur.

Amazing performance when you consider that it is a pushrod type and most of these do not offer the same level of precision as parallelogram derailleurs.

They are much sought after and one of these in NOS condition can cost well over $1000.00

From Classic Lightweights UK...