can't read?
PMMA Microspheres. Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass.
Poly(methyl methacrylate) or PMMA microspheres are often used as spacers, medical fillers, and cores for metal coated spheres in a wide variety of applications including porous ceramics, self assembled microfluidic devices