Presently we produce tungsten-nickel-copper sinkers for fishery usage , which have higher density than lead sinkers and whose density can be changed from 14.0 g/cm3 to 18.3 g/cm3 at users� disposal.Compared with traditional lead sinkers, tungsten alloy sinkers have many advantages, such as environment-protect property, because they don�t contain poisonous element , don�t pollute the environment and do no harm to human beings.