Storage Upgrade IV

The Storage Upgrade (IV) is an item added by Storage Drawers. It increases the maximum storage of a Drawer by 16 times its base value. For instance, with only one installed it will increase the maximum storage to 512 stacks from 32.

Trivia
You do not have to use previous tiers for this to work. You can have the Tier IV without the Tier III.

The storage increase will stack if you install multiple Storage Upgrades.