The Progrip XRT Rope Lock Tie Down Features Coated Hooks and a Solid Core Polyester Rope. Break Strength: 350 lbs. XRT means Extreme Rope Technology, and is simple and easy to use. This patented device uses specially designed ribs to lock the rope inside the wheel hub and is easily tightened with one hand. The ratchet feature on the wheel set lock the rope and prevents unwanted tension loss. A simple thumb operated release trigger disengages the ratchet lock to unwind, when you desire. Precision injection molded housing resists corrosion in extreme weather conditions.