Cover Plates are constructed of a durable brass or chrome alloy with a concealed hinge for covering existing floor sleeves • All attachment screws are concealed when cover plate is in closed position, allowing for a completely flat and safe playing surface • Standard cover plates have a 5" I.D., with a total diameter of 6¼" • Oversized cover plates have a 6-5/8" I.D., with a total diameter of 8".