We are re offering following windows for various applications 1. BK7 Window2. Fused Silica Window3. Sapphire Window4. CsF2 Window 1. BK7 Window The Window is made from BK7 material, which has transparent range from 330-2100nm. The refractive index is 1.5164 at 588nm. The BK7 window has good performance over visible and near IR spectrum for most application.