These pH indicators have been impregnated with a mixture of several indicators. On contact with the sample solution they assume a particular colour. A check against the colour comparison table supplied allows the pH to be determined.

• Instant pH readings
• Accurate for a wide range of routine pH testing
• Convenient and portable for field use

The book format is particularly suitable for educational and industrial use. In schools this format is economical because the amount of paper per student can be carefully controlled.