•Produced by a Specialty Gas Manufacturer in a batch; for cylinder to
cylinder homogeneity (currently 4 companies produce NTRMs)
•Cylinders are analyzed over time
•Data is reported to NIST
•NIST requests at least 10% of the batch be
sent to NIST and NIST performs its own analysis
•NIST “names” the batch
•NTRMs can have less uncertainty than SRMs