3-1/2" Malleable Iron Clamp Backs offer a rugged solution for providing space between mounted conduit and a variety of mounting surfaces. This Clamp Back is designed to be used with malleable or aluminum conduit straps. Malleable iron, due to its strength, rigidity and ductility (ability to flex without breaking) makes these straps highly resistant to damage caused by crushing or physical abrasion. Zinc plating offers even greater corrosion resistance over time. These Malleable Iron Clamp Backs are available in trade sizes 1/2” through 4”.