Surface treatment of the growth area developed by TPP optimally enhances the proliferation of the cells She gripping ring: often copied, never reached! prevents accidental dropping of the dish bottom. Serrations in the gripping ring render the dish grip secure Yellow marking area on side of the lid, frosted on side of the bottom Stacking ring on the lid and corresponding ridge on the base provide an extremely secure stacking feature. Vents provide airflow between stacked dishes for consistent growth conditions and prevention of condensation Cams on the inside of the dish lid function as spacer and enable a constant movement of air and limit condensation Numeric "clock" markings (12, 3, 6, 9) in the base of the dish divide it into quadrants for quick orientation