Provided with calibration to NIST traceable standards. Range: 800 Kilohms - 10 Megohms. NIST Calibrated: Calibrated with accepted procedures and standards traceable to the National Institute of Standards and Technology. Made in America. "Compliance verification should be performed prior to each use (daily, shift change, etc.). The accumulation of insulative materials may increase the foot grounder system resistance. If foot grounders are worn outside the ESD protected area testing for functionality before reentry to the ESD protected area should be considered." (ESD SP9.2 APPENDIX B - Foot Grounder Usage Guidance). "A log should be maintained which verifies that personnel have tested their personal grounding devices." (ANSI/ESD S20.20 Paragraph 6.2.2.2 Personnel Grounding Guidance). "Frequency of Functional Testing: The wrist strap system should be tested daily to ensure proper electrical value. Nominally, the upper resistance reading should be less than or equal to 10 megohms or a user-defined value." (ANSI/ESD S1.1-2006 Annex A3).