Black rock is yet another stylish rock to use in planted aquariums. It's easy to work with, eye-catching and affordable. They're also stackable which means you can create a nice effect in your tank with very little problems. If you are stacking, use Just Fix It - a product that sets hard stopping the rocks from toppling over - click here to view it.
Each bag consists of 6 pieces of rock on average but gross weight of 5kg.
Finally, it's worth noting the picture is purely an example of what is available - not the exact pieces you will receive.
The selection of rocks range from 10-20cm long.