Phydrion Jumbo Pencil pH Indicators

A precision method for surface testing pH of a variety of materials. Readings closely approximate those made with a pH interchange meter. Tests are conducted by using distilled water on the surface to be tested, make a mark with the pencil, and wait a few minutes until color stabilizes and match to chart.   

Pencils test within full pH range of 0 - 13. Box contains 3 pH pencils.