Petri dishes used for cell cultures have to remain intact to prevent contamination. The stacked rings on the dish protect the tissue cells apart from providing secure grip on it. The raised ring will be useful while opening and closing the petri dish. The embossed arrows available with the 100*20 option will help the technician to orient the lid to its dish. The raised stacking rings offer a number of advantages including safe and aseptic handling, safe storage and optimal gas exchange due to correct fitting of the lid.