Strips provide accurate colorimetric pH indication without bleeding into solution. For greater accuracy immerse indicator strips for prolonged period when testing weakly buffered solutions. Made of a plastic strip on which a dye is covalently bound to the paper carrier. This plastic strip (6 x 85 mm) has four different indicator dyes that are colour-fixed and non bleeding so test samples are not contaminated during measurements. Gradations are 1.0 pH for 0.0 to 14.0 pH range and 0.2 to 0.5 for the rest.