Because they are loosely coupled, the highest order modes excited by overfilled LED sources experience higher loss in the fiber, at fiber bends, and connections than low order modes. A mandrel wrap placed on the test jumper that is attached to the source during referencing and during testing of the cabling serves as a "high-order mode filter" and will provide greater consistency of measurements than using a Category 1 CPR source without a mandrel wrap. The effect of a mandrel-wrap on an overfilled light source is illustrated in figure 24