Calibrated batch to batch with accurately printed colour charts Comparator pH Strips are extremely simple to use and measure pH with. Robust results and maximum quality is strengthened by our ISO 9001 certification and high quality raw material. Our Comparator Strips have been a global standard for many years. The Comparator brand consists of a product portfolio differentiated by a range of pH values and incremental steps between 0.2 - 0.5 pH units. These Comparator Strips are manufactured to have a unique single pad system of impregnated paper, which allows the resultant colour change to remain up to 5 times longer when compared to the standard comparator papers.