The Rheem Performance Platinum 50 Gal. Electric medium water heater provides an ample supply of hot water for households with 3 to 5 people. This unit comes with two 5500-Watt stainless steel heating elements and an automatic thermostat which keeps the water at the desired temperature. Plus One Water Management control includes multiple user modes and water sensor with audible alarm. A 240-Volt electrical connection is required for installation. A patented magnesium anode rod design incorporates a special resistor that protects the tanks from rust, providing longer tank life. Factory installed temperature and pressure relief valve and 3/4 in. water connections are included with the water heater for easy installation. This model has a 12 year limited tank and parts warranty plus a 3 year in home labor warranty. This Rheem Performance Platinum model is Wi-Fi compatible allowing for remote monitoring of the water heater's operation (Wi-Fi Module REWRA631EWH sold separately).
Ok, so that's how a sacrificial anode works. What the hell is a "special resistor" and how does that provide longer tank life?
I have written Rheem now on this a couple of times, with no response. They market this all kinds of ways calling it a special resistor,
Longer Life: Patented magnesium anode rod design incorporates a special resistor which protects the tank from rust.
Longer Life: Patented magnesium anode rod with resistor protects the tank from rust
Doing a Google patent search showed CA 2569779 C: Improved resistored anode construction.
But, I have no idea if it works or if it's nonsense, and how effective it is.