As stated in the post, Pokémon can now hold two items, To avoid being too unreliable, I added some rules; let's go over them👇
You can't use the same item twice, like 2 Rocky Helmets.
You cannot use two damage manipulation/berry items.
Ex: No 1 Sitrus Berry and 1 Passo Berry/Choice Scarf and Band
But you can use Sitrus Berry and Leftovers, Choice Scarf with Mystic Water
But you can't use Mystic Water and Charcoal, the same goes for Leftovers and Black Sludge.
Special items like mega stones and Z-moves take up 2 slots.
Attacks and abilities that affect items will affect the item you equipped first, and then the next item.
Example: Knock Off will remove the Sitrus Berry you equipped first, and then the Choice Scarf if used again.
I don't know if I complicated things, but hope you understood.
by Caio-Chomp