A fence panel and gate configuration whereby there are only two horizontal members (stringers) built into the panel or gate.  Not available on fencing over

A fence panel and gate configuration whereby there are three horizontal members (stringers) built into the panel or gate.  Two of the rails are at

An aluminum fence panel and aluminum gate configuration whereby there are four horizontal members (stringers) built into the panel or gate. All residential fence panels

American Architectural Manufacturers Association.  http://aamanet.org

A mixture of different metals where aluminum is the predominant ingredient.  Premium aluminum alloys are widely used in engineering structures and components where corrosion resistance