Bigger stacks

The upgrade icon in BTD4.

BMC Bigger Stacks

BMC artwork

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.