Although it has a lower block rate compared to other, smaller shields, Blackoak Shield has a number of other interesting properties that make it worth using.
Perhaps the most noticeable ability of Blackoak Shield is its large potential of absorbing Cold damage. It may have the potential for being able to absorb the most Cold damage out of any item, which when combined with other Cold Resist equipment (e.g. Hawkmail, etc.), could help boost a player's Cold Resist to very effective levels as far as Hell Difficulty.
Along the same lines, although Blackoak Shield does not make a player immune to being frozen, it does half freeze time, which is useful as freeze time increases to very long time periods in later game.
Although Blackoak Shield does not have as high chance to block, it does have quite a Faster Block Rate bonus. It also has a small chance of casting Weaken when struck; not an intensely useful ability, it is handy when surrounded by legions of monsters that are physical attackers.
Required Level: 61
Required Strength: 100
Chance to Block:
Paladin Smite Damage: 17 To 29
+160-200% Enhanced Defense
+ (0.625 Per Character Level) +0-61 Absorb Cold Damage (Based On Character Level)
+ (1.25 Per Character Level) +1-123 To Life (Based On Character Level)
+ (0.5 Per Character Level) +0-49 To Dexterity (Based On Character Level)
+50% Faster Block Rate
+4% Chance To Cast Level 5 Weaken When Struck
Half Freeze Duration
(Only Spawns in Patch 1.10 or later)