According to the  school, a paramanu (atom) is an indestructible particle of matter. The atom is indivisible because it is a state at which no measurement can be attributed. They used invariance arguments to determine properties of the atoms. It also stated that anu can have two states—absolute rest and a state of motion.
They postulated four different kinds of atoms: two with mass, and two without. Each substance is supposed to consist of all four kinds of atoms. Atoms can be combined into s (triads) and  (dyad)before they aggregate into bodies of a kind that can be perceived.  Each  (atom) possesses its own distinct  (individuality) 
The measure of the partless atoms is known as parimaṇḍala parimāṇa. It is eternal and it cannot generate the measure of any other substance. Its measure is its own absolutely.