Dakine makes great leashes whether for surf or flatwater SUP. You wouldn't want to use this one for surfing, but it's great for racing and flatwater touring. It does what it's supposed to by staying coiled on the board to reduce your drag. If you're paddling in saltwater make sure to give it a rinse after. All that salt will eventually seize up the bearing in the rail saver if you don't.
This leash is long enough without being too long. It attaches to the board easily. Most importantly it's very comfortable to wear.