Neutral Litmus pH test paper tests for Neutrality of a solution, or its acidity or alkalinity, does not come with a color chart, test strip will turn red if dipped into an acidic solution (pH <7) or blue if dipped into an alkaline solution (pH >7), Size: 100 test strips
Double Convex Lens, Highly polished, optically true lens is excellent for physics classroom demonstrations in optics and light refraction, with ground edges, great for physics classrooms, with highest grade, Size: 250 mm focal length, Lens measures 1.5in diameter, 0.2 weight