Streak boosts are special bubbles which can be gained by getting 6 matches in a row without missing.
The button shows how close you are to getting the streak boost
This shows the button when the streak boost is ready to go. Simply press the button to add it to your launcher
There are 4 types of streak boost, but only one will be available in a level.
Destroys bubbles within a large radius
Destroys bubbles in a row
Shakes the pack, dislodging up to 10 bubbles
Destroys bubbles in a column