No, but ultra green is a very popular softer more flexible leader material. I am using a once popular on the West Coast, and a lot of salt water leaders were made with it called Velux..no longer made, but a somewhat softer, flexible leader material. It is also possible to twist the butt section, and end up with a loop in both ends. I can't do that because I forgot how the guy showed me. At the show, the MFGer of the Nor-Vice (Norm Norlander) demonstrated at his booth how to make them in various ways. The fellow that showed me has his wife help him. He starts with the single strand, say 9', and his wife securely holding the other end. He twists positioned 9 ft. away from her, and when he sees the twists reach her, and not too tight he has her come to his end, and he secures it, and now he has tight twists..granny knotted off, and twists retained. I took my 4 wt. and out to my test pond/lake that my city just built, and casted into a fairly good breeze...the leader turns fully over with ease. I've seen differences of opinion over the years as to what transfers the energy best in the butt section...harder stiff mono?...or softer mono. Twisted of course you do increase the stiffness some, add wt., and in essence, double the diameter. I do know that my neighbor here in town, RIO LINE Co. sells the most leaders out here for sure, and they use the biggest butt diameter of any. If others would use a .021 for a 9' 4x they use .023 for the same leader...a little heavier, and stiffer turning over the leader better. If you do it yourself sitting on a chair, you twist with both hands towards you, and the downstream hand has to constantly run your hand downstream freeing up the mono, and not letting it get tangled. I go down aways twisting, then back, and making sure I have a smaller loop at the beginning. The more you twist the more the mono wants to twist, and it becomes easy. You can tell when you see the twists fairly close together, and no opening up of twists as you go that you have it tight. Doesn't appear to me so far that a fly barb can catch between a twist..it is as one. I think it may depend on your waters, and power applied casting in general. You may like the more subtle laydown of the commercial guys 8lb Maxima, and twisted virtually all the way out to the tippet you use. I'm a big water guy, and fully load most of the time, and the twisted butts work great. And I don't know if it makes a difference either way.