A range of instruments has been developed to meet virtually every requirement for inspection of each stage in the application of a coating system. Many such instruments are manufactured by Elcometer Instruments, Ltd. Functions performed include inspection of the substrate, checking the suitability of climatic conditions, testing the coating thickness when wet and later when dry, and assessing the adhesion, integrity, and physical appearance of the coating. This article describes the various Elcometer instruments available for quality control in coating system application.