# 📐 L2 Spec — Magnetic Flux Leakage (MFL) — pipeline & rail inspection Mismatch-Only Spec
**ID:** `L2-121-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-121`](/artifact/l1/L1-121)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41554215
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 64 – 1024 |
| W | px | 512 – 32768 |
| Snr db | dB | 0.0 – 35.0 |
| N sensors | — | 8 – 256 |
| Lift off mm | mm | 0.1 – 10.0 |
| Velocity mps | — | 0.1 – 20.0 |
| Velocity effect | — | 0.0 – 0.3 |
| Liftoff variation | — | 0.0 – 0.5 |
| External interference | — | 0.0 – 0.3 |
| Magnetization non uniformity | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
16.0 + 0.3 * SNR_dB - 10.0 * liftoff_variation - 6.0 * magnetization_non_uniformity - 0.2 * velocity_effect * 20
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`4148bcb9b825cb1e48f31f079821fe0c8b4a5e97abc6e5dd6ff3d9c917dabfcc`
## 5. On-chain Registration
- **Chain hash:** `0x656a8d6f47c1e37b5d30c0a5e6028e595e3fe8f20d26700292e411cb6aa5cc24`
- **Chain tx hash:** `0xfd6f0d15795770d8f161a2d731cd519ae32e9564b0310d33af872e202b0a9527`
- **Chain block:** `41554215`
---
## File Mapping
This bundle consists of: `L2-121-001.md`, `L2-121-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-121-001.md` | Source of truth — edit this | Human or LLM |
| `L2-121-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-121-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._