KRS 5 Middle Window (Optistat CF/DN new style).
KRS 5 (Thallium Bromide-Thallium Iodide) is a useful window for the mid IR. The complex nature of the cold window mount and the necessity to make it vacuum tight results in the clear access diameter being reduced by 2 mm when compared with other materials. The material is toxic and should be handled with care. Measuring 26mm diameter x 1mm thick