REOSC has developed a new hard multispectral coating on ZnS compatible with military environment conditions. In extreme conditions the coating exhibit a pretty good behavior. Developed on ZnS, other substrates can be used. The coating itself can be tuned from UV up to 10micrometers . High transmission in visible spectrum >= 90 percent is achievable for an antireflection coating tuned around 8-10 micrometers on ZnS. The coating is laser compatible.