Koch offers nine styles of Synthetic Air Filter Media for use in air filtration systems of all types. This broad spectrum of products is designed for use in Koch Pad Frames, and is also available in bulk rolls for customers preferring to cut their own pads. Koch Synthetic Air Filter Media is primarily used as a prefilter for more expensive final filters, often extending the life cycle of these final filters by 50% or more. Koch Filter® Air Filter Media Roll, Series: SPT10, 90 ft Length, 40 in Width, 0.14 in WG, 255 g Dust Holding, 0.86 Dust Weight Arrestance, Polyester/Synthetic, Blue/White