Your CAT dealer can get it.(may have it in stock, too) They show the part number in their old "Safe Source" booklet.(generic book for bolt, nut, hose, etc part numbers)

 Mechanics use it to find leaks sometimes, even use it on fuel systems, too, for hard to find fuel leaks at injectors, with a slight crack in housing area.

I know they have red, and green, maybe one other color, too.