3M™ Glass Bubbles HGS19K46 are hollow glass spheres designed for use in drilling, completion, and workover fluids, as well as cement slurries for the oil and gas industry. With a nominal density of 0.46g/cc and an isostatic crush strength of 19,000 psi (pounds per square inch), HGS19K46 are wellsuited for use in deep to ultra-deep wells.