So Natural Black River is a dark, heavy mix with strong binding properties. This means it is perfect for using on the feeder or balling in on rivers. Being heavy will ensure that it goes straight to the bottom before breaking up. It is a slow acting dormant mix that is ideal for carrying other baits such as chopped worm and casters to the bottom or it can be added to other groundbaits to make them heavier and bind better for fishing in faster flow or deeper water.