Buffet Crampon S1
This is an early S1, probably built on an Super Dynaction body. See the picture of the engravure. Buffet started to build the S1 series in 1973, they ende the SD series in 1975, very shortly before this instrument was built. The key system is S1 all the way, with all the remarkable constructions (low e flat/c, side f sharp, high f sharp, left pinky table).
It is silverplated an in a very good condition.