Multispectral ZnS is made from Standard ZnS by a post-deposition hot isostatic process. This process spreads the transmission band to visible(0.4-12um), thus makes the material clear like water. Multispectral ZnS showing excellent transmission across the visible to long-wave infrared waveband, with very low scatter and absorption, is well-suited for the applications that require a single aperture for beam path for several wavebands. Highly recommended ZnS Optics from Yutai Optics:
ZnS lenses, domes
ZnS Prism
ZnS Windows