This Corning microplate lid is made of rigid polystyrene. Lid has a corner notch on the A1 corner to correspond to the corner notch found on all Corning microplates. Sterilized by gamma radiation. Lid does not fit Corning 2µL 1536-well microplates. Sterile. Material: Polystyrene. Plate Format: Lid. Surface Treatment: Not Treated. Corning #: 3099.