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These retarder plates are made from quartz for 1/4 and 1/2 first order. The plates are suitable for low power and high power applications.
Reynard Corporation standard parameters apply:
Thickness: 2mm ±0.2mm
Substrate Material: Crystal Quartz
Surface Quality: 20-10 Scratch & Dig
Flatness: < 1/8 Wave @ 632.8nm
Parallelism: < 0.5 seconds
Outside Diameter: 25mm