NAVIGATION
Silver chloride crystal optic disc, 32mm x 3mm, polished both sides
Zinc selenide crystal optic disc, 13mm x 1mm, polished both sides
Calcium fluoride crystal optic disc, 38mm x 6mm, polished both sides
Potassium chloride crystal optic disc, 38mm x 6mm, polished both sides
Sodium chloride crystal optic disc, 38mm x 6mm, polished both sides