If you buy recycled lead blocks with the DDNZS stamp, you help the "Dive the North Sea Clean" foundation with cleaning the North Sea. Anglers lose a lot of fishing weight while fishing in the North Sea, because the line with the lead attached to it easily gets hooked on lost fishing nets or pieces of wreckage. DDNZS clears away the lead because the fishing hook continues to fish (called ghost fishing). Lead is also a toxic substance that does not belong in the marine environment. It is estimated that Dutch anglers lose 1 million kg of lead in the North Sea every year.

The lead recovered by Duik de Noordzee clean divers is melted down under safe conditions into DDNZS diving lead in various sizes and shapes. You use the lead in combination with a double set.