Buttons

Buttons are small items that occasionally drop from Bloons. Normal Bloons have a 0.005% of dropping one. Blimps have a 0.12% chance to drop one. Bosses always drop one, but if you're lucky you get 2. Chances of Button drops are multiplied by x0.3 in Freeplay mode, making them much rarer.

Buttons can have 2, 3, or 4 holes. You can equip ten buttons of each type. You can hold an infinite amount of buttons in your inventory. More powerful Bloons drop higher qualities of Buttons, and also qualities of buttons dropped increase as you rank up.

Perks of Equipping Buttons
Buttons gain perks based on their quality. Perks are randomly generated based on the quality they have and the quality required.

Any Quality that couldn't be used when the button was generated increases tower damage. Each unused quality point increases tower damage by 0.5%.

Perks from all types of Buttons

 * Popping Power increased (4 Quality Required per 1%, limited at 50%)
 * Tower Firing rate increased (10 Quality Required per 1%, limited at 30%)

Perks from Buttons with 2 Holes

 * Special Missions give more Monkey Money (8 Quality Required per 1%, limited at 50%)
 * M.O.A.B.-Class Bloons take more damage (6 Quality Required per 1%, limited at 60%)
 * Bloons are slower (12 Quality Required per 1%, limited at 10%)

Perks from Buttons with 3 Holes

 * Beating Impoppable Mode gives more Monkey Money (6 Quality Required per 1%, limited at 40%)
 * Towers regenerate X% of their max health every 10 seconds (14 Quality Required per 0.1%, limited at 3%)
 * Towers have more health (12 Quality Required per 1%, limited at 45%)

Perks from Buttons with 4 Holes

 * XP goes up quicker (11 Quality Required per 1%, limited at 30%)
 * Tower range increased (3 Quality Required per 1%, limited at 30%)