I agree with sidespin47, I use the Seagar Inviz X on everythining expcept top water and FnF, because it does sink and can pull your bait down. Of course, I only fill my spools with about 50 to 100 yards of Fluorocarbon becasue of the cost. I have found that not only does the Seagar Invez X have all the great properties mentioned in the previous replies, but it also seems to stay fresher on the reel longer, so I'm not changing out my line as often. Here's a tip: use a cheap green line (doesn't matter the pound test) as your backing line under the fluorocarbon so you can see when your getting close to the end of the flouorocarbon. The green line will show through the clear line. I guess the red line would work well too.