New, custom made sapphire sight windows that can withstand applications from UHV to 10,000 psi and cryogenic to 1,000°C along with abrasives and caustic chemicals have been introduced by Meller Optics ...

We have had 2 windows replaced due to gases inside the panes leaking. Kolbe honored their warranty without question & sent their own installer out right away to order the custom-made windows ...