Pyroquickness Hat is a very rare Hat that burns the wearer when casting a fire spell, but also grants them an extra Bonus Action.
Merely holding the circlet makes your skin flush, filling you with determination and righteous fury.
Properties
Helmets 
Rarity: Very Rare
Weight: 0.5 kg / 1 lb
Price: 160 gp
Special
The wearer of this item gains:
- Fiery Return: When you deal Fire damage with a leveled spell, you
yourself and gain an additional 
Bonus action this round.
Where to find
Can be found in the Sorcerous Vault inside Sorcerous Sundries, in the vault of Elminster. It is inside an invisible chest. 
or 
can be used to see the chest.