All stainless steel construction with nylon mounting brackets that will fit both 7/8" and 1" tubing. Designed to be mounted on either vertical or horizontal rails as well as any flat surface. Designed to allow antenna wire to feed directly through the base. Sea-Dog Line is a 3rd generation family company with a history of satisfied customers stretching back to the company's start in 1933. The company is the recipient of multiple industry awards for quality and efficiency.