This is a good example of needing MODEL number......
(pictures very helpful)
With the ECO (Energy Cut Off/Hi Temp t-stat) and the T-stat (normal temp t-stat) being installed on backside with the element then the water heater is 2003/previous year model
ECO---OPENS at 180*F
T-stat,,,,,opens at 140*F
Element is a screw in version and the 6 gal/10 gal use the same set of t-stats
Atwood part number 91873 (110V AC set)
Atwood 91873 Water Heater ECO Thermostat 110 VAC