Improved Hammer of Justice is a talent in the Protection tree, you will need to spend 7 points in Protection to max it.
Rank table
Rank
Cooldown decrease
1
10 sec
2
20 sec
Tips
Most bosses and some high-level mobs are immune to Hammer of Justice. Therefore, most PvE paladins do not spec this. On the other hand, it is an important talent for PvP paladins.