Feature:
1. Light weight,economic cost,washable
2. Simple structure and convenient filter material replacement
3. Low resistance,,large filter area and air volume
4. Cardboard frame with special process, with long working time,economical and durable
2. Simple structure and convenient filter material replacement
3. Low resistance,,large filter area and air volume
4. Cardboard frame with special process, with long working time,economical and durable