1kg contains up to 155 to 160 balls. I am not guaranteeing howmany balls but im guaranteeeing 1kg of amount of balls. Because howmany piece that makes a kg is relative. It might even be more than 160 in some kinds of bio balls.

Packaging of this item might be in a nylon bag because we shear per kg from a larger sack.

The bio balls helps to trap living/ micro organisms so it dosnt over crowd the pond. It is basically a place where living organisms can live. They are trapped as water recylates. 

It is an effective way to control growth of algae etc in the pond/ aquariums.