Well got the Kastking round level wind reel and so far really impressed with it. So ordered some Kastking Copolymer 4# line for one of my spinning reels. All I can say is wow! tuff is so thin I can barely see it. Might have been different 40yrs ago, I didn't need glass's then, 20-15 vision! I had to hold the stuff up to a window and get a lot of daylight on it to tie knot's with it. Stuff is 0.18mm thick. No idea how I'm ever gonna see it laying on the water! Pretty sure a fish won't be able to see this stuff. Going after Catfish tomorrow, if it don't rain, so won't get to try it out till probably Saturday or Sunday.