Tracerline® Dye-Lite® All-In-One™ full-spectrum fluorescent dye easily pinpoints leaks in all oil and oil-based fluid systems, including engine oil (includes synthetics), fuel, automatic transmission fluid, power steering and hydraulic fluid (petroleum-based). All-In-One dye ensures optimum leak detection in marine vessels systems because it actually contains two distinct fluorescent dyes. One dye fluoresces best under ultraviolet light, and the other under blue light. So whatever type of inspection lamp is used, All-In-One dye is sure to produce a brilliant glow.