This newly patented Airgas® Smart Indicating Line Regulator (SIR™) provides final point of use pressure control while maintaining gas purity for gases 99.9999% pure or better. The SIR line regulator safeguards the instrument from contaminates that are in the gas stream. These may be from system leaks, components in the gas deliver system, or have entered the system during cylinder change out. The SIR line regulator safeguards the instrument or process if a lower grade of gas has been connected to the system or a purity issue exists with the gas. SIR regulators also provide a visual indication if leaks have developed downstream of the regulator. The purifier turns color if there is a problem in the gas stream. When the purifier changes color from the top down, it is removing impurities in the gas stream. These impurities may be from gas that is less than 99.9999% pure or from contaminants that entered the gas stream during cylinder change out. If the purifier turns color from the bottom up, the system has a leak downstream of the regulator. When the entire purifier has changed color, it simply needs to be replaced. The purifier has a patented quick-change base to allow for easy change out of spent purifiers. The base has integral check valves built into the self-piercing connectors. These check valves allow the spent purifier cartridge to be changed without exposing the gas stream to contamination. The regulator portion is specially cleaned for all analytical applications and will not generate contaminates that consume the purifier. The built-in safety relief valve protects instruments downstream, as well as the purifier, in the event of a regulator failure.