Purple (or violet) polymer microparticles of high sphericity and tightly defined particle size distribution are used in industrial and scientific applications for process control, diagnostics, and medical device technology. These spherical polyethylene beads are specifically designed with density ~1g/cc for suspension in fresh water, enabling flow visualization and PIV analysis of fluid flow in a device. It is often advantageous to color code the particles by size to better understand which part of the process the spheres of the specific size were able to pass through, or where the contamination in the process is coming from. Microspheres are supplied in dry powder form and are color stable in solution. No solvents are used in the manufacturing process. Polyethylene is inert to most solvents.

Other colors, sizes and grades of polyethylene spherical particles are available:
Polyethylene Microspheres (Colors, Fluorescent, Phosphorescent, Barium Sulfate)
Other neutrally buoyant particles for flow visualization and PIV are available:
Microspheres for Flow Visualization and PIV (1.0g/cc)