The PRO-Series Flush Mount Base for Existing Concrete is designed to be recessed into existing concrete surface and provide a permanent support for the installation of a davit arm. Unique round plate design allows for recesses to be cut using readily available core drills,12 diameter for the plate and 4 diameter for the sleeve tube. Large,symmetrical bolt pattern reduces the size of concrete anchor required which simplifies installation.The Base sits flush with the surrounding surface to eliminate trip any hazard and may be covered with a sleeve cap when not in use to prevent contamination. Mild Steel/CS-500 Part # 30021 Mild Steel/Hot Dip Galvanized* Part # 30018 304 SS/Sandblasted* Part # 30022 316 SS/Sandblasted* Part # 30038