Spacer-grade microspheres are highly spherical and free of odd shapes and angular particles. Their high sphericity, close size tolerances and high mechanical strength and chemical durability make them ideal for all applications that require these high-grade standards. Spacer-grade microspheres are presently used in gas plasma displays, automotive mirrors, electronic displays, flip-chip technology, filters, sporting goods equipment, calibration standards and other applications. Tightly sized solid glass spheres are used in adhesives as a bond-line spacer. Glass spheres with high crush strength are incompressible and are added in small amounts to adhesives and resins to define the bond-line thickness.