Direct pH measurement on paper and leather is fast and accurate with the HI 99171 pH meter. HI 99171 utilizes a flat tip probe designed to optimize surface contact with the sample. pH measurement of papers and cartons is important, not only in the production phase, but also in the packaging phase. The food industry, for example, perform pH compatibility tests. Order Information: HI 99171 is supplied with HI 1414D flat tipped pH/ temperature probe, HI 70004 pH 4.01 buffer solution sachet, HI 70007 pH 7.01 buffer solution sachet, HI 700680 electrode cleaning solution for cellulose deposits sachets ( 2) , HI 70960 conductive electrolyte solution for pH measurement ( 30 mL) , batteries, instructions and hard carrying case.