As critical as it is to use the proper purifiers to remove contaminants, it is also important to use the plumbing and regulation items to insure a leak-free delivery system. Any leak, no matter how small, can compromise the quality of the gas. Additionally, the gas must be delivered to the point of use within the pressure requirements of the instrumentation. Some of the highest quality and best known companies (such as SSI, Swagelok, and Airgas) are represented by the following products.