Endless Furling Line for GX Top Down Furlers.GX Top Down Furlers--For Racing: An asymmetric spinnaker measures the same as a regular downwind sail if it has a mid girth of at least 75% of the foot length. This means you can combine the furler with your regular spinnakers without penalty within the ORCi and IRC rules. This will increase your tactical options and will allow for faster and easier headsail changes.Top-down-furling: The sail is attached to the freely-rotating tack swivel on the drum and to the halyard swivel while the luff is free flying. A rigid anti-torsion line connects the drum and the halyard swivel. When turning the drum the anti-torsion line makes the top of the sail furl first, while the tack is independent on its swivel. This makes for a tightly furled sail from top to bottom. Go to westmarine.com to order an endless furling line and anti-torsion line of the length and diameter that your system requires.