Utilize Discount Strut Accessories 5/8" x 11/16" Electro-Galvanized Steel Square Strut Washers to connect threaded rods & other strut fittings to channels. The 316 stainless steel material is ideal for outdoor use, has superior corrosion resistance, & is great for chemical or saltwater applications. Finish: ST316 Size: Bolt = 5/8"; Hole = 11/16"