Our BHF serial strain gauges using epoxy phenolic as substrates material, excellent with acetal materials used by most manufacturers, and as substrates material of coating as well, copper foil as sensitive grid and manufactured by hot layer compression process, the strain gauge is entire seal structure, which have possessing functions of temperature self-retrieve, creep self-retrieve, high resistance to moisture and humidity, good resistance stability and reliability, low hysteresis, good repeatability, high insulation strength.