Choose by the engineering problemChoose by the engineering problemThermal / general multilayerIS400 · FR406 · 370HR — verify exposure and constructionSignal-integrity taskFR408 · FR408HR · IS415 — use frequency-specific dataSpecialty polyimideP95 core + P25 prepreg — verify HB and thermal missionReleaseExact grade + core / prepreg + copper + acceptance evidenceEngineering illustration · Not measured production evidence · Not to scale