Corning Pyrex Borosilicate Glass Petri Dish Cover Only, 100mm Diameter x 15mm Height (Pack of 12) Cover only; bottom not included Petri dish style: 100 x 15mm; cover diameter x height: 100 x 10mm Made from borosilicate glass code 7740 Beaded rim provides greater mechanical strength and reduces capillary action of condensed moisture Reusable cover will withstand repeated sterilization (wet or dry)