Superlok tube fittings and valves are manufactured with the industry’s only built-in gap gauge. During installation, the compression nut is simply tightened until the gap gauge rings pop off. When the gap gauge rings pop, it signals the installer to stop. This is the point of perfect compression and seal, which provides an added level of safety and accuracy for companies worldwide. Superlok brings the only game changer to the tube/compression fitting and valve market. This patented innovation ends leaks that are caused by improper tightening procedures, and from the failure to check the installation with a gap gauge, which all manufacturers require. The new, leak-free technology is so precise, that Superlok extends a lifetime warranty on all tube fittings and valves. If you want it done right the first time, get Superlok!