Re: Embarrassing confession
Furled leaders for trout are usually made from tying thread, so they do need to be treated with floatant, and although synthetic, it helps to let them try thoroughly (and possibly washed) after use.
The end has a small loop to which you attach your tippet.
The advantage is that they have no memory and don't kink or twist, since they are essentially a very fine mult-strand rope. Turn-over and presentation of small flies is improved. Even though I don't have patience for them, two of my fishing buddies swear by them.