It includes a black plastic center cap. It roughly measures 15 7/8 diameter. It has a tapered square shaft, as shown in the pictures. It has some minor scratches and scuffs from storage, as shown in the pictures. This is new old stock and does come as shown with only parts shown. For more information regarding this item contact a dealer in your area. (SH / LOC: 121 B / 9045495) (3). The item "MERCURY VINTAGE 15 7/8 RIDE GUIDE STAINLESS STEEL STEERING WHEEL MARINE BOAT" is in sale since Tuesday, February 23, 2016. This item is in the category "eBay Motors\Parts & Accessories\Boat Parts\Controls & Steering". The seller is "parts1d414" and is located in Franklin, Wisconsin. This item can be shipped worldwide.