Lyphan strips are manufactured with the indicator and the comparative color scale combined on one strip.
Since the measurement scale is on the same strip as the test scale, both are dipped together into the liquid to be tested. Measurement is faster and more accurate because both the scale and test have come in contact with the same colored liquid, which eliminates inaccuracy.

Lyphan strips come in packages of 200 strips, and if kept dry and in a dark place, they will keep for several years.
They are manufactured in a wide variety, which covers the entire pH range from 0-14 without gaps.

Instructions for use pH indicator paper (strips)
Hold the indicator strip at the top and dip it into the solution so that the entire strip is moistened.
It’s very important that they not be dipped more than 1 or 2 seconds because this particular indicator paper is not designed to tolerate a longer immersion time.