Quality Control Cover glasses offer uniform thickness and size, exceptional clarity, and excellent resistance to corrosion. Produced with unusual attention given to rigid control procedures, from manufacture to packing. Every cover glass is totally free from fingerprints, striae, and oily film. A solid plastic box is designed to stop contamination, lint, and sticking that is found often in normal packaging. Items are packed conveniently one ounce to a box, and 10 ounce boxes to a carton.