Superflite is the ONLY manufacturer of pre shrunk surface tapes.  These tapes offer less than 3% shrinkage, making them perfect for dark colored airplanes sitting out in the sun.  The pre shrunk tapes work best on straight areas, like the ribs and longerons.  Because there is only 3% shrinkage left in these tapes, you can iron them without worry about the edges shrinking in.  The pre shrunk tapes do NOT work well on wing tips because there isn't enough give left to allow them to stretch around the curves appropriately.