This mast base union will come with a $10.00 stainless steel nut. The rubber union has cracks in it and will need to be replaced soon . The two stainless steel bolts that hold the rubber union in place seem to be frozen .Feel free to ask questions before bidding .This product is a Windsurfing Mast Union Base. Its aspects are unknown, but it is being sold for parts or not working. It falls under the category of Water Sports and specifically Windsurfing.