Hooks are designed as either single hooks—a single eye, shank and point; double hooks—a single eye merged with two shanks and points; or triple—a single eye merged with three shanks and three evenly spaced points. Double hooks are formed from a single piece of wire and may or may not have their shanks brazed together for strength. Treble hooks are formed by adding a single eyeless hook to a double hook and brazing all three shanks together. Double hooks are used on some artificial lures and are a traditional fly hook for Atlantic Salmon flies, but are otherwise fairly uncommon. Treble hooks are used on all sorts of artificial lures as well as for a wide variety of bait applications.
