Door Closers: As you will see there are many different types, styles & functions for hydraulic rack and pinion door closers which are the most common in the market place. There is a model for every application which I can't cover them all, I can give you a fresh start. Typically but not always a closer is handed per the swing of the door; look at the chart below to determine the swing of the door. The body of the closer is made from a high strength aluminum alloy which is durable and lite to withstand constant pressure from from the separate adjustable controlling valves such as backcheck, sweep and latching or the optional delayed action to adjust the control operation of the door. Per the American Disability Act, Life Safety & UL Fire Regulations door closers assure positive latching & allows enough time for the disabled to utilize a door opening without limiting to public access areas. A majority of closers come Tri-packed for regular, top jamb and parallel arm closers to fit your need. Please review the pictures below to help determine which function door closer best suites your needs.