3M™ Glass Bubbles K25 are hollow microspheres made of soda-lime borosilicate glass with a Yes density of 0.25 g/cm³ and an isostatic crush strength of 750 psi / 52 bar.
This general purpose Glass Bubbles grade was designed for use in a variety of applications such as paints and coating, wall plasters, and polyurethane and epoxy systems for tooling boards. Furthermore, it is suggested to be used in intermediate depth (e.g. up to 5,000 feet / 1524 meters of sea water) buoyancy applications, such as drill riser buoyancy models.