The unique recessed lid on this dish offers excellent stacking stability and space saving. It works with most models of media pouring equipment, absolutely a must for a manual pourer. Four ventilation lugs on underside of lid allow for venting, and prevent condensation from developing and dripping on the culture. The extremely flat bottom allows a reduction in the amount of media required. Patented cross ribs on the bottom make the dish resilient and resistant to warpage when the media is poured at a high temperature.