This is a bag of expanded clay terracotta balls or beads to use either as a drainage base for your pot or as an alternative medium for your plants with added nutrients to replace soil. The pebbles and beads in this assortment vary in size from 0.32" or 8mm to 0.62" or 16mm. Adding these below your soil helps balance capillary action and is lightweight. 

Sold by weight of 1/2lb.