Aggre-Gator® Hex Washer Head 300 Series Stainless Bi-Metal Concrete and Masonry Fasteners Print The Aggre-Gator anchor is a bi-metal screw anchor for light to medium duty applications in concrete and masonry block base materials. The Aggre-Gator is fast and easy to install and provides a neat, finished appearance. Aggre-Gator anchors provide excellent corrosion resistance in demanding applications, such as those in exposed environments. Read Less