Purify your water of heavy metals with this refill substrate for use in water purification. It is extremely expensive because it is very hard to make in this pure form and critical for many water uses. Ultra purity is necessary for it to irreversibly bind to and render inert: Hg, As, Cd, Pb, and most divalent heavy metals from water through a percolation type filter or ion exchange resin. It can remove a wide variety of heavy metals from many different mediums including water. It is sold in 10-gram quantities.