These pH Test Strips are perfect for a variety of uses; whether you're conducing a science experiment or testing your pool water or your favorite beverage, they provide an accurate reading every time. Each vial contains 100 pH test papers, which are divided into five booklets of 20 strips each. This makes it easy to ensure that you always have a fresh strip on hand. They measure the entire pH range from 1-14 in 1.0 units. Whether you're a beginner or an expert, these strips are the perfect way to test the acidity or alkalinity of any liquid. Each strip measures approximately 63mm long and 10mm wide.