The ARO-Flo Series sets the standard for air flow performance. These FRL solutions can keep your facility online and your equipment in shape because we combined best-in-class air flow performance with the flexibility to work in any environment. Filter-regulator, or piggybacks, combine the functions of both a filter and regulator. Piggybacks are compact and most effective when space is a constraint. Piggybacks can be ordered with different filter elements and can be modified with different springs, depending on the filtration and air regulating requirements.