A wide variety of experimental assays require a series of washes. Microplate washers are laboratory instruments designed to control the procedure of washing experimental samples arranged in plate-based formats. Users load a plate and select a program; microplate washers then dispense, soak and aspirate liquids from the plate in seconds. Compared to manual alternatives, microplate washers tremendously improve the speed and accuracy of many different washing procedures, and are particularly useful for Enzyme-Linked Immunosorbent Assays (ELISAs). Microplate washers are also employed to wash cell cultures, protein arrays, Western blots and beads as well as applied in DNA purification protocols. The capabilities of microplate washers are determined by several parameters. Microplate format compatibility (48, 96 or 384 wells), the number of channel heads (6, 8, 16, 96 or 384), the number of liquids dispensed (1 to 5) and the range of volumes dispensed and aspirated (10 microliters to 3 milliliters) all vary by instrument model. In general microplate washers are designed to leave only 2 microliters of residue per well and operate with an accuracy of <3% CV per well and a uniformity of <4% CV across a plate. All microplate washers enable users to program tank selection, volumes, step times, and cycles for customized procedures.