4.5" 1/2"-20 UNC Jack Plate Bolt Kit (DK6145) by Seastar Solutions®. Stainless steel bolts, brass nylock nuts and stainless steel washers. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet your needs and deliver great quality at an affordable cost.