ITEM NAME:2Pcs BF350-3AA BF350 Precision Resistive Strain Gauge For The Pressure S FES Hn.Sensitivity coefficient(gauge factor): 2.0 - 2.20. Strain limit: 2.0% (2000 microstrain). Materials:Conductive material: Constantan, copper-nickel alloy 55% copper / 45% nickel (constant resistance over temperature).