KnuckleHead Strut supports are designed to support a wide variety of equipment, including mechanical units, solar panels, pipes over 3 inches in outside diameter and duct work. The KnuckleHead line is molded with glass-reinforced nylon which has aluminum like properties. Glass-reinforced nylon is tough, weatherproof, UV stable, and impervious to freeze-thaw cycles. Each KnuckleHead can support up to 600 pounds of weight. The standard universal base is 7 inches in diameter, the optional Big Base is 12 inches in diameter and is recommended in free-standing applications over 12" in height. The Strut KnuckleHead is height adjustable from 3.25 to 5 inches in total height by rotating the head, based on the use of 1 5/8 inch strut. KnuckleHead extensions are available for applications exceeding this height. The KnuckleHead line can free free-standing or mechanically attached using Green Link Adhesive/Sealant and/or fasteners.