![Red Litmus Paper, 100 vial](http://www.homeeducationalresources.com/cdn/shop/products/11561_{width}x.jpg?v=1396401645)
This is a type of pH test paper used to determine the acidity or alkalinity of a solution. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic(i.e. alkaline) conditions. This is a vital tool for classroom projects or field trips. They are supplied in a clear plastic vial containing 100 3mm x 12mm strips.