NO. :TWA-1 500G Name: Surface Glue Ceiling Filter with TC Fabric This series is the economic development of TWB-2, we still use longer hot melt anti-broken fiber and water resin. The only difference is that we use the production method of surface glue spray in order to reduce the cost to meet the economic demands in the markets, the capacity of dust holding and the filtration efficiency are lower than the solid glue filters. The requirements for air pressure are lower.