https://www.avient.com/knowledge-base/article/what-s-difference-fillers-reinforcements?ind[]=6598
1http://pottersbeads.com/egm/NorthAmerica/Products/SolidGlassMicrospheres/SPHERIGLASS.aspx
2http://polymer-additives.specialchem.com/centers/solid-glass-beads/properties 3http://pottersbeads.com/egm/NorthAmerica/Products/HollowInorganicMicrospheres.aspx