Nylon. For traditional Attwood pole lights. Hinged cover snaps closed to keep dirt and water out when light is stowed. Four countersunk holes for installation. Includes 7-1/2″ hard wire leads for connection to 12 VDC power supply. Dimensions: 2-1/4″L x 1-3/4″W. 1-1/4″ diameter installation hole.Base fits the following poles: Frosted globe 5100 series standard pole & 5110* series locking collar pole; Anti-glare 5320*, 5330*, & 5340* series; Pulsar bi-color poles 5092*. (*when locking-collar is removed).