Dispensers deliver set volumes of liquid straight from the reagent bottle, replacing pouring and repeated pipetting with one repeatable stroke. Bottle top dispensers cover 0.5 to 50 ml across four volume ranges, with accuracy within 0.5% and precision of 0.1%, and withstand vapour pressure up to 500 mbar for volatile solvents. Electronic bottle top models add motorised dispensing for high-volume work, while dispenser and diluter systems combine dispensing and dilution for preparing standards. Chemical-resistant bodies handle acids, bases and organic solvents. Typical uses include media dispensing in microbiology, titrations in analytical labs and reagent aliquoting in pharmaceutical QC.