Unlike spring-activated cord locks, the KnotBone Cord Lock #3 has no moving parts that can slip, jam with snow or ice, break, or rust. Its simple design allows you to secure the ends of pull cords of all kinds to the exact tension you need, and it will keep them absolutely locked in place until you release it. To use, simply thread both ends of your cord through the Cord Lock #3's closed end, pull to the desired tension, wrap and lock. It's the perfect knot-free way to secure and lock cords. Made of lightweight, durable plastic for years of dependable use.