If you're wondering what size binder you will need for a Obsidian Flames Master Set with no cards stacked on top of eachother, we recommend a 12-pocket binder with 480 pockets. 

 

Here's the set breakdown:

• 197 Numbered Base Cards

• 176 Reverse Holo Base Cards

• 33 Secret Rare Cards
   

Optional Extras (requires a 12-Pocket binder with 480 pockets):​

• 4 Stamped Cards

• 18 Variant Cards

• 7 Scarlet & Violet Promo Cards

• 8 Basic Energy cards

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In total, a complete Obsidian Flames Master Set contains 443 unique Pokémon cards including the optional extras.