Levasil CA420 PNH is an alkaline, aqueous dispersion of colloidal silica that is approximately 40% solids by weight. The silica dispersion is ammonia stabilized and the amorphous silica particles carry a negative surface charge. The silica particles are discrete, have a slightly rough, spherical shape, and are present in a narrow particle size distribution. The physical appearance of the dispersion is a translucent liquid, slightly more viscous than water with the recognizable smell of ammonia. Levasil CA420 PNH is produced primarily for the North American market.