The Bow/Stern Eye Is Unc Thread And Available In Sizes Ranging From 3/8" To 1/2". Each U-Bolt Includes 4 Nuts (2 Standard And 2 Beveled), 1 Bow Plate And 1 Stern Plate. It Is Made From Grade 304 Stainless Steel For Corrosion Resistance And Durability, Making It Perfect For Marine Applications.