I found this rather nice picture of a REV I with tails that I built in 1994. http://home.arcor.de/johnmitchell2/3-Photo...30504-41_wm.JPG At the time such a design and material was not available from the mfr. The material is Icarex P31. The tails are 15 meters(50ft) long and are also made by me from Icarex P31. The tails are cut with a hot razor knife. They are much better then the nylon counter part as the slip very easy amongst each other except when damp.