Stanley Black & Decker owns DeWalt, Black & Decker and Stanley. Their 18V packs share rails but not notches.
Watch out: Same rails but different notches (DeWalt 5-slot, Black & Decker and Stanley 4-slot). Only fits with physical modification, which voids the warranty and is not recommended.
| Brand and line | Voltage | Sold at | Version | Membership | Notes |
|---|---|---|---|---|---|
| Black & Decker 18V lithium | 18V | – | 4-slot | Reported | |
| DeWalt 18V XR | 18V | – | 5-slot | Reported | |
| Porter Cable 20V Max | 20V | – | Not recorded | Inferred | Slot pattern not recorded. |
| Stanley Fatmax V20 18V | 18V | – | 4-slot-v20 | Reported | Owners report the same 4-slot pattern as Black & Decker, but adapters are sold between the two, so treat them as different packs until confirmed. |
Voltage labels differ by market: many “20V max” packs are the same nominal 18V pack.