Corning Pyrex 90 mm Diameter Plain Watch Glass/Beaker Cover

These 90mm diameter PYREX watch glasses are designed to fit 400 mL PYREX beakers. They possess high chemical durability, thus preventing contamination of solutions. They are molded to the same radius of curvature for convenient stacking. The heavy wall and uniform fire-polished edge provide mechanical strength. The outside diameter cannot be controlled within close limits and a slight degree of out-of-round can be expected to occur.