Recommended for tanks aged and very dirty. Tank Prep A & B removes the rust and free the tank from the oil and water before applying the sealant final (KRM Tank Sealer). The KRM manages to seal the cracks capillaries (the holes no!) and tight the tank from the inside, while protecting it in time against rust. A bottle is sufficient for a tank from the capacity of 13 liters. Kit sold in a pack of n. 3 bottles.