Manufactured from SUPRAX® 8488 borosilicate glass, these optical pressings ensure optically clear / undistorted readings, through the use of bubble-free / striae-free glass qualities and quality fire-polished surface.  Available in diameters from 76 mm, products are thermally tempered to ensure safety, for applications such as water meter glasses in pressurized applications. Special glasses for non-pressurized applications can be manufactured without thermal tempering.