It is efficient, reliable, timesaving, economical and is in regular use in thousands of workshop all over the world. It is unbelievably simple to use to check fluid systems, pour the appropriate Dye-Lite fluorescent dye into the fill port and inspect with the UV/blue light lamp. For A/C systems, hook up the hose to the service port, inject Fluoro-Lite dye using the injector and inspect with the lamp.