https://www.solidsealing.com/products/2142/0-40-Inch-View-Diameter-CaF2-157nm-VUV-Grade-Window-in-a-304-Stn-Stl-1-33-CF-Flange/
0.40 Inch View Diameter CaF2 157nm VUV Grade Window in a 304 Stn. Stl. 1.33 CF Flange - Solid...
Solid Sealing Technology hermetic Viewports: FA48780-11 - 0.40 Inch View Diameter CaF2 157nm VUV Grade Window in a 304 Stn. Stl. 1.33 CF Flange