So what the heck is IM6 and IM7, have you ever wondered. These are trade names of the graphite product. It is the Hexcel Corporation that produces this kind of products. Basically these numbers are a label for standards and quality. These is because other companies also use these designations to refer to graphite not made by Hexcel. The simple allow you to compare quality of the materials used to build the graphite rods. So the big difference in the labels are this you can be confident that the IM& rod uses better graphite in there build then the IM^ rods. Of course this only works if you are looking at 2 rods from the same company, it does not work if you are comparing 2 different rods from 2 different companies, that is very improtant to know.
Fiberglass on the other hand has been around since the 1947 and has come along way since the early years. Fiberglass is recognized for it soft action and overall toughness, and is a great material for rod building.
Fiberglass rods are often preferred for throwing crankbaits, or whenever an application of a medium to slow action is required.
Fiberglass is made with a variety of glasses, such as Sand (silicon dioxide) or Limestone (calcium carbonate). These 2 are then mixed with other ingredients such as sodium carbonate, potassium