# 📐 L2 Spec — Guided-Wave Ultrasonic Testing (long-range pipe/rail inspection) Mismatch-Only Spec
**ID:** `L2-122-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-122`](/artifact/l1/L1-122)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41554215
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| F khz | kHz | 10 – 500 |
| N time | — | 512 – 16384 |
| Snr db | dB | 0.0 – 35.0 |
| N modes | — | 1 – 5 |
| Range m | m | 1 – 200 |
| Mode mixing | — | 0.0 – 0.5 |
| Temperature drift | — | 0.0 – 30.0 |
| Coating attenuation | — | 0.0 – 0.5 |
| Support reflections | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
14.0 + 0.3 * SNR_dB - 10.0 * mode_mixing - 0.1 * temperature_drift - 6.0 * coating_attenuation
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`34b8300396cb588fcb904c730c9f6d61e43cc9a030c041d731071b9d43534a6f`
## 5. On-chain Registration
- **Chain hash:** `0xc8ff7936b661f8c6b61ae65237e171d0ff36a74437264e68a902471ddcb0c569`
- **Chain tx hash:** `0xb67229014c01c592a88839adf779a28e368ba2810654d47d871188a18cd6c3ab`
- **Chain block:** `41554215`
---
## File Mapping
This bundle consists of: `L2-122-001.md`, `L2-122-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-122-001.md` | Source of truth — edit this | Human or LLM |
| `L2-122-001.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 `L2-122-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._