Square/Flat Rail Mount or Side (Bulkhead) Mount This all 18-8 stainless steel mount attaches to any vertical flat surface such as bulkheads, hulls, transoms or cabin sides. Also mounts to square or flat rails. Fits HORIZONTAL RAILS up to 2-1/4 (57 mm) high by any depth or VERTICAL RAILS up to 1- 5/8 (41 mm) wide by any depth. Rod portion of mount quickly disconnects for easy storage. Some fasteners required for installation. This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.