Pauldrons of the Unrelenting are plate shoulder armor for tanking. These pauldrons are a substantial upgrade over Pauldrons of Might due to increased Armor and Defense, as well as +dodge instead of +block. They can be a small upgrade over Pauldrons of Wrath due to having superior Defense as well as +dodge instead of +block value, though set bonuses may make Wrath a better option.
It should also be noted that these Pauldrons are notoriously unattractive. They look like green-dyed leather shoulderpads with purple trim.