The C melody saxophone is a tenor saxophone pitched in the key of C, one whole step above the B-flat tenor saxophone. In the UK it is sometimes referred to as a “C tenor”, and in France as a “tenor en ut”. The C melody was part of the series of saxophones pitched in C and F intended by the instrument's inventor, Adolphe Sax, for orchestral use. Since 1930, only saxophones in the key of B♭ and E♭ (originally intended by Sax for use in military bands and wind ensembles) have been produced on a large scale. However, in the early years of the 21st century, small-scale production of new C melody saxophones has commenced in China for a company called Aquilasax. (source)