CE Smith Trailer 15501A Square U-Bolt with Washers & Nuts, 7/16" x 2-1/8" x 4"- Replacement Parts and Accessories for Your Ski Boat, Fishing Boat or Sailboat Trailer Square bend 7/16 inch -14 diameter thread 2-1/8" w x 4" L WARNING: To reduce risk of nut seizure when using stainless hardware always apply a light coat of grease prior to assembly