Milbank 6002 Plastic Meter Blank Blank Cover is designed to prevent access to a meter socket when the meter is not in place. The circular cover is compatible with both ringed and ring less style meters. The cover is installed with 4 included plastic tabs. Blank-Out Covers are the perfect solution for meter boxes that require a meter to be removed from service, while still maintaining a safe environment. These covers are made from fiberglass reinforced polycarbonate. They fit virtually every socket for single phase electric meters, including 320A meter sockets.