Yellow Flute
From PokéHeroes Wiki
A Yellow Flute is an item that doubles EXP/EHP increment of your Pokémon & Eggs for 24 hours.
How to obtain them
They can be found and bought at the Item Shop for 23 Nuggets 
.
How to use it
It can be blown and activated from your party page.
Other
- Yellow Flutes are not tradeable.
