Adolphe Sax cor solo

A very rare instrument by Adolphe Sax. Original E crook on this cor solo. Additional two Cornford crooks for F and G.
 Perhaps the only cor solo from Sax left. The French horn player Didier Vivier, friend of Rossini and an excellent soloist, played a cor solo by Sax. Number 8800. Paris around 1850.