The TN-100 is a replacement inline zinc pool anode for the (TN-IL). Inline Anodes have become a "must install" component in salt water pools for many top builders. These builders believe that Inline Anodes solve the complex corrosion problems present when salt system sanitation is used. Anodes are designed to corrode and protect other metal components in the pool. Greater surface area means more protection for the pool components. The anodes mass (weight) determines the amount of protection an anode can supply until it has completely corroded. A sheet of zinc foil with a large surface area and small mass will provide a lot of protection over a short period of time as it will quickly corrode away. A zinc ball with a large mass and relatively small surface areas area will provide a small amount of component protection over a long period of time. TechNode Anodes are designed to provide maximin protection yet have reasonably long expected anode life. This combination of anode mass and high surface areas makes Perma Cast anodes the most efficient anode in the pool industry. Compare TechNode's specifications with the competition. This concept was patented by Pool Tool Company in 2010 under U.S. Patent 7,688,116 B1. PERMA-CAST is the choice of professionals.