Use this product to mount on a rail. Rail size 1" or less, otherwise you will have gaps under fitting. We suggest using bolts and nuts or stainless steel rivets to mount to a metal rail. When using a bolt be sure to use a flat washer and locking nut. Stainless steel deck hinges work best with stainless steel eye ends. Cast Type 316 Stainless Steel. Concave Deckhinge with bolt.