Bases for Perko Pole Lights are now sold separately to give you more choices for customizing lights for your specific needs. Bases are selected to match the designed rake angle of the pole light with the number of pins (electrical contacts) necessary. Rake angle of 0 and 5 degrees are common on later production boats, 16 degrees are often found on pre-1980 year boats. All-round pole lights use 2 pins, and removable combination masthead and some plug-in bi-color pole lights with an accessory light require bases with 3 pin contacts. Key Features Collars secure the pole light into the base Collar types available include an eccentric cam design and large threaded versions Waterproof Snap-On or slide covers