Buying Swivels?

Swivels are an important detail in fishing and are primarily used to prevent line twisting. This is especially true for baits that rotate, such as spinners or when trolling and bombarda fishing. Swivels are also used as a connecting link between two lines and for stinger rigs in predator fishing with large rubber baits.
Size-wise, swivels do not follow a direct standard like hooks do, but it can vary a bit depending on the manufacturer. The size is denoted by a number. The higher the number, the smaller the bait lock. Size 12 is a small swivel, 4 is significantly larger