These polystyrene dishes with flat-bottom wells incorporate the Nucleon-treated surface for optimal cell attachment and growth. Useful in all areas of cell culture including scale-up and cloning. Raised well rims to lower risk of cross contamination. Lids are keyed for a one-way fit. Rings in the lids reduce evaporation and condensation. Writing areas on both lids and dishes and individual alphanumeric markings allow easy identification of samples. Non-toxic and certified no pyrogenic. Stackable.