The ultra high precision FRSM is based on the new generation Z1 Foil Technology of the Bulk Metal® Foil resistor elements by VFR Resistors (a VPG brand), which makes these resistors virtually insensitive to destabilizing factors (for more information about stresses and destabilizing factors please refer to Tech Note 102: www.vishaypg.com/doc?63135). Their element, based on the Z1 Foil Technology is a solid alloy that displays the desirable bulk properties of its parent material; thus, it is inherently stable (remarkably improved load life stability of 25 ppm), noise-free and withstands ESD to 25 kV or more. The alloy is matched to the substrate and forms a single entity with balanced temperature characteristics for an unusually low and predictable TCR over a wide range from –55°C to more than 175°C. Resistance patterns are photo-etched to permit trimming of resistance values to very tight tolerances.