PYREX 75mm Diameter Ribbed Watch Glass/Beaker Cove

Corning These 75mm diameter ribbed PYREX® watch glasses are designed for use as covers for 250mL PYREX® beakers. Ribs are molded into the glass so that they can't pop off as they do when cane is sealed to standard watch glasses. Permits escape of excess vapor and eliminates risk of contamination from dropped hooks or props. Meets EPA requirements for methods 3005, 3010, and 3020. - COG