Can anyone clarify the different IM ratings for me supposedly IM7 and IM8 Rods are build from better graphite material which is more sensitive than say IM6 does anyone know what to look for when buying a rod with the different IM ratings as some quality rods still could be made from IM6 graphite for example Musky rods etc is it because you do not need to have a sensitive blank when fishing for Musky as you obviously do not need to feel what the fish is doing in order to set the hook as you would with say a walleye?