Purging Monitors & Balloons (Click for more Info) You’ll know exactly when it’s safe to begin welding because it tells you when the residual oxygen concentration of the purge gas is low enough. This means you no longer have to rely on guesses and can save both time and reduce purge gas consumption. These monitors are essential for any welding application that requires critical weld standards to ensure the quality of the weld is not compromised by a contaminated atmosphere. With the Weld Purge Monitor, Welders and Welding Engineers can ensure they have the optimal conditions for consistently producing high-quality, repeatable welds.