... 2000 and GB/T 19001-2000... 1. We can produce pre-filter with paper frame, which has different efficiency from G2 ... shipment3) Manufactured under ISO9001 standard5. There is our list of pre-filter as follows: Dimension(mm)Rated Air Flow(m3/h ... than 15 countries, including Canada, USA, Australia, Italy, Hungary, Thailand , Vietnam, Yemen, Venezuela, Iran, Bangladesh, Georgia, HK etc.Reason 8Delivery can ...