For lower right the first deciduous molars. (S/84)
Paired with P-1.

For bicuspid root with festooned serrated beaks.

For bicuspids, especially for subgingival cavities with deeply festooned serrated beaks.

For lower bicuspids with flat serrated beaks.

For upper and lower bigger bicuspids with flat serrated beaks.
A little bigger than 2T