Royal Wire's single wire hooks are made out of 3/8" diameter basic steel & then zinc plated or powder coated to guard against rust & corrosion. Recommended usage with other Royal Wire products: 3-Tier Bridle rack, Main Frame, Hat Can Holder & 3-Tier Wall Basket Unit. This hook fits over a cement block. Our 30 Inch Single Wire Cement Block Hook is perfect for lowering your Royal Wire. This hook was designed with the World Equestrian Center in Ocala, FL tack stall walls in mind.