There are many different surfboard leashes of varying lengths and thicknesses.
Generally they fall into these five categories:
Designed for the every-day surfer and is typically 6 feet long and ¼ inch thick. You can also get longer and thicker ones depending on the length of your board and preference. Good brands are Dakine, Ocean&Earth, FCS and Creatures.
Thinner and lighter than a regular surfboard leash. It creates less drag in the water and is used in surfing contests and smaller waves.
3 SUPER LIGHT
The lightest surfboard leashes on the market. They are hollow so therefore not as strong as regular leashes. Mainly used by groms on smaller surfboards. Likely to snap in bigger waves.
4 BIG WAVE
The Big wave leash is much stronger and thicker than regular leashes. This is to cope with the forces of big waves. They are typically between 7 and 12 feet long and usually up to 5/16 inches thick. Many big wave leashes feature a quick release pin so they can easily detach the leash when in a dangerous situation.
Longboard leashes come in two different types, calf leashes or ankle leashes. The calf leash is attached to the calf of your leg, the ankle leash just above the ankle. This leash is much longer and thicker than a regular leash so it can withstand the forces of the wave plus the extra weight of the longboard.