The Decoy Heavy Lock is great when you need your weight to stay against the hook. It fits 12lb to 25lb mono or 50-80 lb braid. Most use it for flipping and punching but they also work great for Texas rigged worms or craw baits when you don't want the weight sliding up and down the line. We like the decoy brands because they are long which allows it to come through weeds without hanging up. They also stay on the line and grip it better because of the increased surface area. Simply put your line through the wire loop an inch or two and slide the lock onto the line. It will first go on both lines but will then will slide onto the main line.