TRACE 2 LEAK DETECTOR A red penetrant dye in a polyolester base that is completely compatible with all refrigerants and lubricants. Use to locate the hardest to find leaks under the toughest conditions in low light or dark areas. Leaks show as bright red stains. For refrigeration and hydraulic systems. Fluorescent with any ultraviolet light source. Non-volatile and will not sludge or deposit gum. Clearly visible, even through ice and frost. 4 oz.