A chipboard frame holds an expanded media pad of continous glass fibers that become progressively dense toward the air leaving side. Rust resistant metal grids and stiffener bars reinforce the media to complete the construction of our heavy-duty "5700" bottlecap filters.

The “5700” bottle cap filter is designed for general air filtration in various types of industrial and commercial HVAC systems. Built for long-lasting service life, this model filter is suitable for installation where dust loading conditions are particularly heavy. “5700” bottle cap filters also serve as excellent prefilters for higher efficiency filters.