Crystal-grade polystyrene dishes for distortion-free, optically clear surfaces suitable for microscopic observation of cells. Stacking rings allow for easy handling of dishes. Special venting features associated with the lid facilitate consistent gas exchange during incubation. The frosted handling rim of the dish base makes it easy to differentiate the base from the lid during routine handling procedures. Easy grip dishes offer a more secure hold when handling small sizes. Gamma irradiated, nonpyrogenic.