Our Cell Explorer™ Live Cell Tracking Kit uses a proprietary orange fluorescent dye that gets enhanced fluorescence upon entering into live cells. The dye is a hydrophobic compound that easily permeates intact live cells. The hydrolysis of the weakly fluorescent substrate by intracellular esterases generates a strongly fluorescent hydrophilic product that is well-retained in the cell cytoplasm. The tracking dye has good photostability with robust imaging performance. The kit is particularly suitable for multicolor flow cytometric analysis of cells. It can also be used with a fluorescence microscope equipped with a TRITC filter set. This kit provides an effective tool of labeling cells for flow cytometric and fluorescence microscopic investigations of cellular functions. The effective labeling of cells offers a powerful method for studying cellular events in a spatial and temporal context. This kit is useful for a variety of studies, including cell adhesion, chemotaxis, multidrug resistance, cell viability, apoptosis and cytotoxicity. The kit provides all the essential components with an optimized cell-labeling protocol.