Anode rod vs. plastic plug.
I recently had it explained to me this way:
twood = A
luminum >> Plastic Plug
uburban = S
teel >> Anode
Recently I watched a YouTube vid on cleaning water heaters. The fellow presenting showed an anode that also had an integrated valve. Seems like an OK idea but I'd think removing the rod for periodic inspection would be a better idea. When they get about 50% consumed it's best to replace.
Mine is the 6gal Atwood and I have a couple of spare plugs in my parts bin. The weight of my parts bin may soon exceed that of the WD hardware.
2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
-SOLD- 2012 X23B
-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks