hollow glass bubbles with lightweight Hollow glass microspheres Hollow glass microspheres / Glass bubbles is a kind of micron ultra lightweight inorganic non-metallic glass material with hollow structure. It is filled with thin nitrogen and composed of soda lime borosilicate glass. We supply hollow glass microspheres in several types, which true density is 0.20-0.6-g/cm3 with 2-130m in diameter, compressive strength is 500-8000psi, thermal conductivity is 0.06-0.10w/m.k. It is featured by light weight , high compressive strength , insulation, anti-corrosion , protection , fire prevention, smoothly mobility etc. It is a versatile and high performance newly lightweight filler.