Skoutag RV Magnesium Anode Rod is used to replace the rusted bar in the water tank of the water heater, perfect replacement for Atwood and Dometic models, and other 1/2" NPT threads water heaters. It can effectively prevent corrosion and rusting, prolong the life of your RV water tank. Compatible: Compatible with all models Atwood RV Water Heater. Replacement Part for Suburban 11553. Corrosion Protection: Extends the life of a water heater by attracting corrosive elements in the water. Size and Material Type: Magnesium anode rod, 4.5" long, 1/2 NPT threads, Use a 22mm or 7/8 socket to remove. Note: If the anode rod is mostly consumed, replace it with a new one. Not compatible with 3/4" thread or 9.25-inch Length Rod. High Quality: Magnesium anode rod made of top-quality magnesium AZ63-alloy.