Designed for easy and stable stacking; Plates are constructed from high grade polystyrene; Individual well rings in lid prevent cross-contamination; Easy-to-read alpha-numeric well identification printed in Bold Black Ink; Yellow marking areas on both base and lid; Plates are packaged in transparent easy "peel-off" wrapping; Guaranteed sterile by gamma irradiation; Bulk - 4/sterile pack; Flat Bottom; 64 plates/case