There are several different methods for spheroid formation that can be used depending on your cell type and application. If you are interested in forming many spheroids of varying sizes, a flat bottom Ultra Low Attachment coated flask or a spinner flask could be used. If you would like to assay single spheroids of the same size, we would recommend Corning 96-, 384-, or 1536-well spheroid microplates. If you need to produce many spheroids of the same size, we would suggest the Corning Elplasia 24-well or 6-well multi-well plates. Corning Elplasia microplates also may be used to generate multiple spheroids per well in order to increase assay response signal or cell number, if that is what your assay requires.