a filter housing having a collar;

a damper coupled to the filter housing and adapted to regulate flow through the collar;

a damper position indicator configured to indicate a flow rate through the collar, wherein the damper position indicator comprises a scale secured to the filter housing;

a damper adjustment mechanism accessible from an exterior of the filter housing, wherein the damper adjustment mechanism comprises a threaded member accessible from the exterior of the filter housing, the damper adjustment mechanism configured to set the flow rate of the flow through the collar by adjusting the threaded member of the damper adjustment mechanism relative to the scale of the damper position indicator;

a filter element sealingly engaged with the filter housing;

at least one port configured to provide a metric indicative of the flow through the collar;

a first port arranged to provide access to a metric indicative of pressure upstream of a flow restriction from the exterior of the filter housing;

a second port arranged to provide access to a metric indicative of pressure downstream of the flow restriction from the exterior of the filter housing;

a first penetration formed through the filter housing adjacent the filter element and coupled to the first port, the first penetration configured to permit communication from the first port without providing a leak path thought the filter housing; and

a second penetration formed through the filter housing adjacent the filter element and coupled to the second port, the second penetration configured to permit communication from the second port without providing a leak path thought the filter housing.