Following up on recent pots. I have a reasonably large number of your 'Brick lights' to fit ...
When fitting ... a very simple question arises .... should they be fitted so that the casting is flush with front edge of brickwork (opt A in sketch)
This would mean that as glass is about 6mm thick ... the front Louvre would then be spaced away from the wall.
Or should they be fitted so that the front of glass is flush with front edge of brickwork (opt B)
This would allow Louvre to be flat against brickwork, but runs risk of Louvre 'tightening up against brick work & not the glass ... and thus gasket would not seal .