As are all of our fixtures, the Carriage Lamp is made of high quality composite plastics that do not corrode, peel or rust which stands up to the harsh salt environment of the oceans. This fixture comes as a Compact Fluorescent, Medium Base or 12 volt. To mount it, use a 1/2" PVC pipe or 3" PVC post. Dimensions of the actual fixture are 7 1/2" x 14 1/2".