Consumer grade vials are yellow. They are good for non-critical work, such as hanging a picture on a wall. Professional vials are blue. These vials meet or exceed the federal specifications for accuracy. Products with these vials are recommended for work that needs to be right, the first time and every time.
What is that stuff? The yellow fluid has been around for about 50 years. It was first invented by Empire to improve usefulness of levels. True Blue fluid was introduced in 2004. This special fluid helps make these vials the most accurate and visible in the world. And best of all, tests have shown the color will last for years longer than any other fluid.
The meniscus is the very edge between the liquid and the gas that makes up the bubble.
The blue lines on the ends of the vial are very important and patented. These lines reflect a dark blue outline on the meniscus of the bubble.
The outside of consumer grade vials is basic, run-of-the-mill plastic… great for occasional, around the house use. The True Blue levels use Armored Vials. These are the strongest vials on the market and are backed with a lifetime warranty.