The right hand trill keys are above the gravity line to reduce the risk of water in the tone holes.
The left hand controls three such tone holes plus the normally open one below the bell.
There are two varieties of tone holes, straight and rolled.
They each have their own ways of making their rolled tone holes.
The lower tone hole of the kuisi sigi is rarely used.
This is a metal band or ring, placed between the voicing window and the top tone hole.
The left thumb operates both a tone hole and the register key.
These tone holes let the player produce every note of the chromatic scale.
Because early clarinets used felt pads to cover the tone holes, they leaked air.
There was an option to have either drawn or soldered on tone holes.