The Lyons C Clarinet plays every note over the entire clarinet range. The fingering system is 'basic Boehm': this means that the way the notes are played is the same as on standard clarinets except that there are no duplicate fingerings, i.e. just one possible fingering for each note. Transition between the standard clarinet and the Lyons C clarinet is therefore easy since no new fingerings have to be learned; and changing from Lyons to standard, you would just have to learn the duplicate fingerings, when appropriate.

See the fingering chart which shows all the notes from E below middle C to A, three and a half octaves higher.