Metal-on-Fused-Silica Neutral Density Filters (250 nm to 635 nm)

This Standard Reference Material (SRM) is intended for use in the verification of the transmittance and absorbance scales of spectrophotometers in the ultraviolet and visible spectral regions. SRM 2031c is a transfer standard certified using the NIST Materials Measurement Laboratory Transfer Spectrophotometer (MMLTS) with traceability through the NIST second generation High Accuracy Spectrophotometer (HAS II), modeled after the original instrument. A unit consists of three individual neutral-density filters in separate metal holders and one empty filter holder, all stored in a black anodized-aluminum container.