The Cal Pro HD Swivel is a high quality, super strong fishing tackle swivel featuring a streamlined design that avoids malfunctions of many standard swivels. The HD (Heavy Duty) Swivel is a powerful swivel that's design is less likely to catch moss or muck from the bottom when compared to a standard swivel design. What's more, because of the streamlined engineering, line doesn't get within the center of the swivel therefore reducing the chance of line fray or tangles. These swivels can be used for freshwater or saltwater applications and will significantly reduce line twist. Very good choice when fishing with main line to leader configurations. The Cal Pro HD Swivels are available in a single #5 size - 300lb strength - 3/4", which matches up pretty well to the Spro Heavy Duty Swivel #5 size. Quantity - 5pk.