Tracer Products' TP-3400 Dye-Lite All-In-One full-spectrum fluorescent dye easily pinpoints leaks in all oil and oil-based fluid systems, including engine oil (including synthetics), fuel, automatic transmission fluid, power steering and petroleum-based hydraulic fluid. All-In-One dye ensures optimum leak detection because it actually contains two distinct fluorescent dyes; one fluoresces best under UV light and the other under blue light. All-In-One dye is highly concentrated, requiring only half the dosage of most competitive dyes.