pH Pencil

This pH Pencil is used to detect alkali or acid residues and may be used to measure the pH of concrete to the nearest full pH value. To measure the surface pH just wet the surface with distilled water. Stroke the surface with the pencil. Wait approximately 15 seconds and compare the resulting color change with the color chart. To advance pencil lead, simply turn the pencil top clockwise. Each pencil will give the user at least 100 tests.