Matched and Unmatched APHA Standard Nessler Color Comparison Tubes

Unmatched sets of Nessler Color Comparison Tubes- The top graduation line on unmatched Nessler Color Comparison Tubes may be any distance from the bottom, but within the scale lengths shown in the table below.  

Matched sets of Nessler Comparison Tubes- The graduation lines of all the nessler color comparison tubes in a matched set will not vary by more than 1.5 mm for the 50 mL and 2.0 mm for the 100 ml sizes, from that of any other tube in the set. The distance of these lines from the bottom of the tube may be anywhere within the scale lengths shown in the table below. Available in Cases of 6 or 12.

Narrower and taller with a much longer scale length than the Low Form Nessler Tubes. The 50 mL size is specifically mentioned by the American Public Health Association in Standard Methods for the Examination of Water and Waste Water. Rings and legend are durable white ceramic enamel. Rings coincide with specific volumes of liquid. Designed from Federal Specification NNN-T-175, Type 1, Class 2 requirements. Tubes feature a "Shadowless Bottom" and durable white ceramic enamel rings and legend.