The flagpole deck or dock mount is a two piece design and has six predrilled mounting holes that will strongly secure the mount to any walking surface. It is made of solid aluminum and powder coated to make it durable for years of service in any outdoor conditions. The base measures 5 inches by 5 inches and the tube is 14 inches tall. The predrilled holes accept a 3/8 inch bolt, hardware not included. It holds all sizes of our portable poles, and other poles up to 1.5 inches in diameter.