Glass Trac 6K Series for extraordinary pressure and vapor requirement.  The method of clamping and sealing the glass differs from other gages in that the glass does not experience stress concentrations imposed by bolting. The glass becomes a floating member between two solidly bolted blocks of rigid plate.  The pressure activated seal principle provides a self-adjusting means of maintaining a tight joint between glass and liquid chamber.  The gasket system compensates for machining variations.