The Desco 50005 Concentric Ring Probe for Surface Resistance Meters is an instrument to be used in conjunction with a resistance meter to measure surface resistance per ANSI/ESD STM11.11 the test method listed in Packaging standard ANSI/ESD S541 for surface resistance of planar materials. The Concentric Ring Probe (Ref: ANSI/ESD STM11.12) can measure the volume resistance of planar materials using a flat conductive metal plate (not included). The Concentric Ring Probe may be used for the resistance measurements of ESD packaging including static shielding and other bags.