HEAT FLOW METER (HFM-100 HT/HFM-100/HFM-50) Heat flow meter for measuring the thermal conductivity and thermal resistance of insulation and construction materials. Best For insulation products, construction materials, packaging, and assemblies In Compliance with ASTM C518 | ASTM C1784 | ISO 8301 I JIS A1412 | EN 12667 | EN 12664