Ferrule or Alignment Dots
Sometimes they are called ferrule dots, section dots or alignment dots. We prefer alignment dots as that is what they are doing; aligning your sections and making it easier to get your sections properly assembled.
There are numerous ways to make this simple process very complicated as indicated in some websites and social media. Our approach is the simplest and easier way to add these dots to your rod. The hardest part is getting your sections aligned just right before adding the alignment dots.
Here are some images showing how simple the addition is: