This is an actual 5.9L tube, not a 6.7L tube like others. Cummins and Chrysler have superseded all their part numbers for a 5.9L connector tube over to a 6.7L tube. The issue with this is that the 6.7L connector tube has a higher likelihood of leaking compared to the 5.9L tube. For this reason, we still sell 5.9L tubes to ensure you have a trouble free injector install. Many also believe they will see a performance increase when switching from a 5.9L connector tube to a 6.7L tube. Although this may be true for some, we haven't seen any gain under the 1,000 RWHP level. If you are planning to stay under the 1,000 RWHP level, then just stick with the tried and true 5.9L connector tubes. Get one or two if you need or a full set of six.