This carbon housing is specifically intended for built-up applications. Structurally reinforced, these modules are designed for multiple stacking and butting to achieve most any desired capacity. Pre-punched alignment holes provide the necessary bolting access for easy installation. Made of 16 gauge galvanised steel, with either 1" or 2" tray or track arrangements available. And 2" or 4" prefilters for initial filtration or system dust, then 2" or 4" after filters for off dusting.