Catalysts are a relatively abundant resource in the Endgame of Path of Exile 2, but new players may find it difficult to understand what the items actually do and how to use them properly.
Not all Catalysts are created equal, and it can be somewhat confusing to understand which ones are worth keeping and which ones are just taking up space in the stash tab for no reason.
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Path of Exile 2: How Do Meta Skills Work
In Path of Exile 2, Meta Skills are special types of Skills that can become absurdly powerful with the right support and proper investment.
How Do Catalysts Work in PoE 2
Catalysts essentially function as special Quality currency for Rings and Amulets but in a different way than regular Quality currency. A 
Blacksmith’s Whetstone
, for example, will increase the overall effectiveness of a weapon by increasing the value of all its modifiers by a little bit. A Catalyst will also increase the effectiveness of a Ring or an Amulet in the same way, but instead of increasing the value of all its modifiers, Catalysts only increase the value of specific modifiers that fall under the same umbrella.
For example, a Tul’s Catalyst adds Quality that only enhances Cold modifiers on a Ring or an Amulet. Now, let’s say a Ring has two modifiers, #% Increased Cold Damage and +# to Intelligence, and you use a 
Tul’s Catalyst
on it. Only the #% Increased Cold Damage value will be increased, +# to Intelligence will be left untouched because it does not qualify as a Cold modifier.
So, in an ideal scenario, players will want to find a Ring or Amulet with at least two or three modifiers of the same type (e.g., flat cold damage, increased cold damage, cold resistance) and use the appropriate catalyst (Tul’s) on them to get the most value out of that Ring or Amulet.
Identifying Modifiers Affected By A Catalyst
The easiest way to determine which modifiers will be affected by a catalyst before applying is by using poe2db. For Rings, head to this page, and for Amulets, head to this page.
Ctrl + F and search for the modifiers you have on your ring. In front of the modifier’s name, you’ll see the tags that define it. Most have only one type of applicable tag, but some have multiple. For example, #% Increased Cold Damage has Elemental, Damage, and Cold tags. But we know there are no catalysts that affect Elemental or Damage tags, only one that increases the Cold tag.
On the other hand, the Leech #% of Physical Attack Damage as Life stat has tags of Life, Physical, and Attack. This means there are three separate Catalysts that will increase this stat: 
Flesh Catalyst
(Life), the 
Reaver Catalyst
(Attack), and the Uul-Netol’s Catalyst (Attack). So, if you have two other Life stats on your Ring, you can use the Flesh Catalyst to get the most value out of it.
Replacing Catalysts
Catalysts can be replaced by one another. So if you use a Tul’s Catalyst to increase the Cold Modifiers on a Ring but later decide you need attribute stacking instead. You can simply use the Adaptive Catalyst on top of the previous Quality to replace it.
Breach Rings And Catalysts
Like weapons and armor, Rings have a maximum Quality of +20%, with the one notable exception: Breach Rings. Instead of +20%, Breach Rings in PoE 2 have a maximum Quality of +50%, the highest in the entire game. This allows Catalysts to increase the value of certain types of modifiers on Breach Rings to absurdly powerful levels. This is why a perfectly rolled Breach Ring with the correct Catalyst applied to it will be more powerful than almost any other ring in the entire game.
How to Get Catalysts in PoE 2
Catalysts are common drops from clearing Breach nodes on the Atlas. They drop both from killing Breach monsters and from the Clasped Hands that appear periodically as the Breach expands. You can increase the drop rate of these items by stacking the ‘Increased Quantity of items dropped’ through Precursor tablets and Atlas skill tree points.
Alternatively, you can easily purchase Catalysts in bulk through the Currency Exchange by talking to Alva in your Hideout and selecting Catalysts.
If you’re using a loot filter like FilterBlade, make sure Catalysts are allowed to be seen in the filter settings. Anything above Semi-Strict hides most Catalysts.
