Universal Indicator Paper pH 1 - 14, Available in 1 reel (5m x 7mm). It is used to test solutions for a pH reading to indicate the acidity/alkali.
 
Usage Direction:
Open the reel and remove some of the paper, using the paper you should test your solution leaving the paper in the solution for around 1-2 seconds. The paper should then be instantly compared to the reel's colour chart to give you a pH reading.