High temperature air filter including the HEPA high temperature , secondary high temperature and perfiler high temperautre, 

The max temperature from 450C-150C in continuously.

Most of the time the frame choose the stainless steel304 (t=1.0mm) ,

The high temperature glue use the special fireplace glue import from Amercian. 

Gasket adpote the glass fibre material so that the high temperature hepa filter can working in high temperature  for long time.