PYREX® 100mm diameter watch glasses are designed to fit 600mL 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. Material: Borosilicate Glass Code 7740. Top Style: Heavy Duty Rim. Fits Griffin Beaker Size: 600mL. Diameter: 100mm (Approx). Reusable. 12/Pack; 144/Case. Corning #: 9985-100.