Selecting the right system size is important. For the majority of vapor sampling projects, 1/4" OD tubing is the industry standard. However, we know that each project is unique; so we offer an assortment of fittings to meet your site needs. It is important to note that although the diameter of the size tubing may change, the "choke points" are going to be your main cause of reduced or increased flow rates. Increasing the diameter of the tubing also increases the amount of line volume needed to purge the system before sampling.