There are square spectacle plates and round spectacle plates.
It is also called a spectacle stone cover.
1mm thick galvalume steel plate with heat resistant coating.
Square type is 460mm x 460mm.
The round shape is 460 mm in diameter.
Both holes have a diameter of 210 mm, so it is possible to pass through a 200 mm double chimney.
Can be used as a chimney cover for horizontal ceilings and vertical walls.