The tooth thickness tolerances can be defined using the selection of tolerance classes according to DIN 3967 or using a custom user input using the 
-button.
The number between 21 and 30 defined the width of the tolerance field and the letter defines the position of the tolerance field according to DIN 3967. The letter 'h' leads to an upper allowance of zero and therefore to a minimal backlash.
Using the -button custom tolerance values can be defined and the measurement ball diameter or the number of teeth to span can be defined.
