On the surface, the Cytometry app by Invitrogen may seem like little more than a product catalog. While it certainly is product-centric, the app warrants inclusion in this column because of the particular organization of the product information into informational/educational categories and because of the built-in protocol features. The app is organized into different categories corresponding to various applications of flow cytometry, including immune-phenotyping, antibody labeling, cell viability, and phagocytosis. Within a given category, the available reagents for that specific type of experiment are given. In this way, researchers are able to get a sense of the types of analyses that are possible and the reagents that are available (albeit just from Life Technologies). Additionally, the complete labeling protocol is given for each reagent, complete with an interactive timer feature for each incubation step. Simply tapping the clock icon will start a timer corresponding to the correct amount of time.