C-3810 High Range Cyanide Comparator is a component of K-3810 Cyanide (free) CHEMets Visual Test Kit and is designed to be compared against the color formed in R-3810 Cyanide (free) CHEMets Refill. The comparator's range is applicable for many drinking water and surface water applications. Color standards are blue in color and cover a range of 0 to 1.0 ppm cyanide (CN-).