• Petri dishes are not tissue culture treated. • Surface is hydrophobic and does not facilitate cell attachment. • 35mm dish has offset bottom for improved handling. • 60mm and 100mm dish features a grip ring on the base. • All dishes are supplied with lids. • Lids contain molded spacers for gas exchange. • Dishes have stacking rings for increased stability. • Packaged sterile (gamma irradiated) in zip-closure bags. Sterility Assurance Level = 0.000001.