This rod is designed for fishing cyprinids, so the thickness of the carbon has been reduced on components 4, 5 and 6 for a more lightweight design.
This also means that these components are more fragile, hence the importance of using extra butt sections specific to medium-distance fishing which will give you something more substantial.
8615816 EXTENSION NORTHLAKE900 R 0.5 m 7 m / 8.8 m
8615815 EXTENSION NORTHLAKE900 R 0.5 m 4 m / 5.6 m
The same is true for fishing with a baiting arm