When getting the maximum amount of casting distance from your chosen weight of lead is important, there is nothing better than the Tournament Casting Swivel design. 

It is a similar shape to the original Distance Casting Swivel lead but is slightly more nose-heavy to ensure that it flies further and is even more stable, especially in any cross wind, and means that you can get away with using a lighter lead than you otherwise might have been able to, and still achieve the same distance. Its streamlined shape also reduces the chances of tangles.