Refractive Index:
1.400 – 1.599


ULC witness samples come with a Refractive Index (Nd) of 1.400 and higher. They are made in America, offering high quality at an affordable price. Characteristics of our witness samples include:

  • Many Popular Glass Types: Select from a large assortment of the most popular glass types.
  • Laser Etched Part Number: No more problems identifying material. The part number is laser etched on the edge and can be cross-referenced to the material type.
  • Inspected per MIL-PRF-13830B: Each sample is inspected for surface quality.
SKU: UL-WS-055 Category:

Additional information

Weight 0.03 lbs

FCD-1, H-K51, H-K9L, L-BAL35, LF-5, LLF-1, N-BAK1, N-BAK2, N-BAK4, N-BALF5, N-BK10, N-BK7, N-FK5, N-FK51A, N-K5, N-KF9, N-KZFS2, N-PK51, N-PK52A, N-PSK3, N-SK11, N-SK5, N-ZK7, PBL-25Y, PBM8Y, S-BAL12, S-BAL14, S-BAL3, S-BAL41, S-BSL7, S-FPL51, S-FPL53, S-FPM2, S-FSL5, S-TIL27, SK-5


25.00mm ±0.20mm


3.00mm +0.20mm/-0mm


< 1 wave @632.8nm

Surface Quality



0.50mm ±0.13mm FW x 45°

Clear Aperture

80% min