3M™ Glass Bubbles HGS4000 are hollow microspheres made of soda-lime borosilicate glass with a true density of 0.38 g/cm³ and an isostatic crush strength of 4,000 psi / 280 bar.
HGS4000 Glass Bubbles are designed for use in drilling, completion, and workover fluids, as well as in cement slurries in the oil and gas industry. HGS4000 are well-suited for use in shallow to intermediate depth wells.