HS-Special Filter Panels, Type HS-GTU, -GTB and -GTA
These consist of different layers of very fine homogeneous glass fibre fleeces with reinforcement of the clean air side. They are non flammable complying with DIN 4102-B1.

HS-Special Filter Panels, Type HS-GT-1000 and -GTF1000
These Filtercells are made from different synthetic fibre high performance fleeces. They have a reinforcement on the clean air side. These filter cells are self extinguishing according to DIN 53 438. The assembly of the filter layers is adapted to the corresponding mounting frame, as follows:

• Type HS-GTU and HS-GT-1000 rigid cardboard
  
  
  
• Type HS-GTB and HS-GTF-1000 elastic cardboard
  
  
  
• Type HS-GTA with expanded aluminum metal cover