I was having a lot of trouble finding the proper line for my new bamboo rod. It is classed as a 4 but my 4 wt line I had wouldn't cast. I tried a heavy 5 wt and I could tell it was too much for the rod. I bought some real silk in 5 wt what a waste of money. Cortland suggested 444 Sylk and I bought a 5wt. It works great. Very smooth.