The best modules in Probably Stolen depend on the machine: Quality modules for the Furnace, the Water Purifier and the Moisture Farm, Performance modules for the Alarm System and the Cryptographic Desequencer, and Efficiency modules anywhere your power is tight. Among the special modules, the Furnace’s Junk Processing Module and the Alarm Transmitter Module are the two worth buying the first time you see them.
Modules are where a machine’s real output comes from, and the wrong ones waste both credits and power. Below is how module stats work, the numbers on each basic module, which stat every machine actually uses, the special modules worth hunting, and where to buy them.
How Modules Work
Every machine that takes modules has a module bay: a grid you drag modules into, the panel marked Module on the machine’s screen. A few rules apply everywhere:
- Stats add up. Each module carries some mix of Performance, Efficiency and Quality, and the machine uses the total of everything in its bay.
- Performance makes the machine work faster or produce more.
- Efficiency cuts the power it uses each night. Negative Efficiency raises it.
- Quality improves what the machine makes.
- Shape matters. Modules are shaped pieces, and the bay starts with some cells blocked, so fitting them is a small puzzle. Module Bay Expansion Kits open more of the grid.
- Machine-specific modules. Universal modules fit anything with a bay, while special modules only fit their own machine, such as a Furnace or an Alarm System.
There is even an achievement for stacking them: Cranked to Eleven asks you to “Reach +250 Quality on any machine.”
The Basic Modules
These are the standard versions. A module’s shape changes its stats, so the ones you find can sit a little above or below these numbers:
| Module | Performance | Efficiency | Quality |
|---|---|---|---|
| Performance Module | About +16% | None | None |
| Efficiency Module | None | About +16% | None |
| Quality Module | None | None | About +8% |
| Overclock Module | About +36% | About -44% | None |
| Eco Module | About -16% | About +32% | None |
| Refinement Module | About -8% | About -15% | About +25% |
The trade-off modules are where the choices get interesting. The Overclock Module buys a big jump in speed with a big jump in power use, the Eco Module does the reverse, and the Refinement Module trades a little of both for three times the Quality of a plain Quality Module. On a machine that only cares about Quality, Refinement Modules are the best use of the space.
Which Stat Each Machine Uses
The single most useful thing to know about modules is that machines do not use all three stats equally. Putting Performance modules in a Furnace, for example, does nothing at all.
| Machine | Stat to stack | What it does |
|---|---|---|
| Furnace | Quality | Every full 100% Quality raises the purity of its ingots by one stage. Performance has no effect |
| Moisture Farm | Quality, then Performance | Quality raises the grade of the water it makes; Performance raises how much |
| Water Purifier | Quality | Quality sets how pure it can make the water; about 100% gets plain water to Pure |
| Alarm System | Performance | Each point raises the chance a theft is stopped; about +50% stops them entirely |
| Mirage Projector | Quality and Performance | Both raise the store attractiveness it adds |
| Cryptographic Desequencer | Performance | Speeds up the work on access cards |
| AgeWell | Quality | Enough Quality ages wine faster |
| 3D Printer | Performance and Efficiency | Quality counts for little here |
Two of those thresholds are worth planning around. On the Furnace, Quality only counts in full steps of 100%, so 99% does nothing more than 0%: build to the line or leave the space for Efficiency. On the Alarm System, there is no reason to go past about +50% Performance, so fill the rest with Efficiency and save power.
Water sellers get the most from this. Our guides to purifying water, removing heavy metals and Ghostwater cover where Quality modules make the difference between a grade that sells and one that does not.
Special Modules Worth Buying
- Furnace Module (Junk Processing). Turns 6 Junk into 4 Scrap Metal on nights the Furnace is not smelting, which makes the Dumping Ground’s most useless find worth carrying home. Our guide to what to do with Junk has the math.
- Furnace Module (Blast). Turns three inputs into two ingots instead of two into one, at the cost of a purity stage. Pair it with Quality modules to win that stage back.
- Alarm Transmitter Module. Adds one point of reputation each night with a faction you choose. It is slow, but it never stops, and a month of it adds up.
- Evaporator Solvent Recovery Module. Makes the Evaporator collect alcohol as pure alcohol instead of losing it. Chemistry runs live on it, and our Evaporator guide explains how it works with Quality modules.
- Chemical Equipment Module. Improves the chemistry machines, the Blender, Heating Plate and Chem Finisher. Our guide to chemical supplies covers the chemistry side.
- Neural Core Module. A contraband module with far bigger stats than anything legal. It carries the same risk as any other contraband in your shop, so keep it out of sight when Security comes calling.
Where to Get Modules
Dr. Jackson is the main source. He sells machines and the modules that go in them, and his stock changes from visit to visit, so a module you want may not be there every time. In a first run, the tutorial introduces him in the first week, when he offers a Furnace and then modules for it. Patch 1.0.0.2 also cut his markup on Normal from 25% to 15%, so his stock is cheaper than it was at launch.
Our guide to upgrading your shop covers Dr. Jackson’s machines and the rest of the upgrade tree, and our guide to making money fast shows where machines fit into a profitable run. Every other guide is on our Probably Stolen hub.
Frequently Asked Questions
What is the best module in Probably Stolen? It depends on the machine. Quality modules (and Refinement Modules) are best for the Furnace, Water Purifier and Moisture Farm, and Performance modules are best for the Alarm System and the Cryptographic Desequencer.
What does Performance do on the Furnace? Nothing. The Furnace only uses Quality, for ingot purity, and Efficiency, for power.
How much Quality does the Furnace need? Every full 100% raises ingot purity by one stage. Anything short of the next 100% does nothing extra.
How much Performance does the Alarm System need? About +50% stops thefts entirely, so there is no point going higher.
What does the Alarm Transmitter Module do? It adds one point of reputation each night with a faction you choose.
Where do you buy modules in Probably Stolen? Mostly from Dr. Jackson, whose stock changes from visit to visit.