Fluorescent Improved Tube Fly System.  By using the tubes as they are, or combining them with dubbing or translucent material you can create a shine like nothing else. Available in Fl.Orange, Fl.Yellow, Fl.Red, Fl.Chartreuse, Black.  Sizes - XS, Sm, Med, Lge.  Please leave one size difference between tubes if you wish to use the smaller Dia as an insert eg XS + Med, Small + Large.  The Frodin cone heads will only fit the X Small tubing, unless bigger tube is stretched.