Bigger Stacks (BTD4-BTD5)

Bigger Stacks is the second upgrade in Bloons TD 4 and the first upgrade in the Path 1 in Bloons TD 5 for the Spike Factory. It allows the Spike Factory to create double sized spike piles, each pile being able to pop 10 bloons instead of 5 per pile.

Prices

 * BTD4: $510 (Easy), $600 (Medium), $650 (Hard)
 * BTD5: $595 (Easy), $700 (Medium), $755 (Hard), $840 (Impoppable)

Trivia

 * With Tack Awesomizer activated, the piles of spikes the factory produces will have 20 spikes in it.
 * This is slightly better than a Spiked Ball Factory without Tack Awesomizer in terms of the popping power, only by 4.
 * Following a Version 22.0 nerf for Bigger Stacks in BTD6, the cost of Bigger Stacks has always increased by $100 with each generation of BTD games.