Max Spider Fluorocarbon connects the terminal knot to the fly. Choose the diameter based on the size of the rig and the conditions of the fishing spot, allowing for some extra strength when fishing near rocks or branches. The Spider Plus is the other option in the line if you’re looking for a slightly more flexible fluorocarbon. The spool holds 100 meters, allowing you to replace the tip without having to change the entire leader. The spool has a diameter of 6.3 cm: check this measurement if you’re using a spool holder.