Sight Glass Disc DIN 7080（seventy eighty ） is also named round sight glass and circular gauge glass, which is made from special formular borosilicate 3.3.（three point three） It is used to observe and illuminate the interior of closed pressure vessels like tanks, silos and other similar installations.

Main Data：
Working pressure:  Depends on thickness and Diameter
Max. Working temperature:  300 °C  (Borosilicate)（three hundred degrees celsius）

Treatment:  Tempered & Polished