https://edgescientific.com/product/em-tec-rxs-6aa-quantitave-edx-analyis-test-standard-with-au-ag-alloys-6-nist-certified-materials-on-pin-stub-2/
EM-Tec RXS-6AA Quantitave EDX analyis test standard with Au-Ag alloys, 6 NIST certified materials...
test standardnist certifiedemtecrxs
https://www.troemner.com/Calibration-Weights/Scale-Weights-and-Test-Weights/ASTM-Individual-Scale-Calibration-Weights/Weight-1P-TEST-Dish-0-005lb-CL6-Accrd-TR/p/80852043
0.005lb Certified Test Weight ASTM Class 6 (RPLC NIST Class F), 80852043
0.005lb Certified Test Weight ASTM Class 6 (replaces NIST Class F) with an Accredited Certificate Item ID 80852043
certifiedtestweightastmclass