Utilize Discount Strut Accessories 1/2" x 9/16" Electro-Galvanized Steel Square Strut Washers to connect threaded rods & other strut fittings to channels. The 304 stainless steel material is ideal for outdoor use, highly resistant to corrosion, & great for chemical or saltwater applications. Finish: ST304 Size: Bolt = 1/2"; Hole = 9/16"