The new Lock Chocks are a new design that keep your chocks with the boat. How many times have you lost 1 or more chocks during a capsize or changing the mast position in heavy swell and wind? Now they will stay while being easy to move. You have the 5mm on one bungee and the 2mm on the other. If you want to mix in some 1mm they can be attached to another small line attached to the mast so they can be placed anywhere you like. They come in 1mm, 2mm, 5mm. They come in red, black, and white. Full sets with end pieces are coming soon.