Filter can be made of Aluminum, Steel or Stainless Steel. The U shape frame was bended from piece of metal sheet, with minimum 3 layers of metal wave - shape net fasten together with a rivet. The minimum thickness of filter was ½ inch ( around 13.5 mm ), However, other specifications and dimensions are customized by the customer.

Carbon Filter contained thousands of carbon particle, in order to help the moisture absorption and deodorization. Due to the small size of particle, a steel plate with hole is required to put on both sides for blocking particle go through, each edge is covered by steel groove, with opening on one edge for the replacement of carbon particles.

Floss Filter generally contained 1 inches thickness of Synthetic Fibre and chicken wire put in front and back, covered by aluminum U groove. The minimum thickness was 1 inch (around 25.4 mm), However, other specifications and dimensions are customized by the customer.

* Hinge Return Air Louver with Aluminum Filter in common use.

White Nylon Filter is woven with nylon silk, so it has cetain toughness, a steel inner frame is required to make it harder, the outer layer is surrounded by aluminum U groove for better protection and appearance. According to customer requirements, we can fabricate a Nylon Filter with more than 2 layers ( Standard ) and the minimum thickness was ½ inch ( around 13.5 mm ), however the actual specifications and dimensions, is depends on the number of layer.

Black Nylon Filter is similar to White Nylon Filter. However, it has only 1 layer ( Standard ) and using steel bar for reinforcement, each edge is covered and seamed wtih black leather, minimum thickness is 6 mm.