Made using high-quality magnesium-material. Our magnesium-rod absorb oxidizing substances and all the contaminants in the water towards itself by electrolys, preventing the water tank from rusting in the metal water tank, ensuring your RV water heater lasting use. These water heater magnesium-anode rods work aluminum ones in attracting elements, protecting your water heater and prolonging its life span with little to no investment. Extends the life of a water heater by attracting elements in the water. If the anode rod is depleted and fully decayed, the water heater will begins to rust, then crack, fail and leak. Use with: For . Unscrew the anode rod to drain the tank. If the rod is mostly eaten , replace with a new one. Always keep a spare in your RV. Colour: Silver + Black Material: magnesium Size: Diameter width 13mm, length 4.5 inches about 115mm Package Contents: 2 x RV magnesium anode rods 1 x PTFE tape (the color of the tape is random, don't accept the specified color) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.