NAVIGATION
Sodium chloride crystal optic rectangle, 41mm x 23mm x 6mm, polished both sides
Potassium bromide crystal optic rectangle, 41mm x 23mm x 6mm, polished both sides
Calcium fluoride crystal optic rectangle, 41mm x 23mm x 6mm, polished both sides
Silver chloride crystal optic disc, 13mm x 1mm, polished both sides
Silver chloride crystal optic disc, 13mm x 2mm, polished both sides
Silver chloride crystal optic disc, 25mm x 2mm, polished both sides