Insta-Chek Mechanical pH Pencil, pH 0-13, 3 per package

Immediately gives the surface reaction of any solid to the nearest pH value|Retractable, nonrefillable, mechanical pencils are more convenient than paper-wrap pencils|The widest range available reading from pH 0 to 13 with 14 different color matches|The handy, easily portable form is perfect for pH spot checks, requiring as little as 0.001 mL of buffered solution. Use pencil on virtually any surfaceeven irregular or uneven ones. It is effective on porous material and impervious solids. To use, first wet the surface or area with distilled water and stroke several times with the pH pencil. After 15 seconds, compare the resulting color against the color chart. Pack includes three mechanical pencils and two color charts.