The TP3400 series UV dye for oil-based fluid systems is perfect for pinpointing leaking engine oil, fuel, transmission fluid, power steering fluid, and more. Pinpoint leaks in deteriorating gaskets and other critical components. TP3400 is fully compatible with oil-based fluids and can safely remain in the system. The UV dye fluoresces a yellow/green color and works with all leak detection flashlights. Please see the instructions for applications and dye dilution ratios.