The Celtic Cornerstone Plaque features an elegant Celtic knot border, a symbol that represents the interconnection of all things and the continuous cycle of existence. Features a handmade, premium grade aluminum casting that showcases an intricate, detailed Irish design. Manufactured from cast, high-density aluminum alloy and protected by our exclusive Alumi-Shield all weather coatings. Alumi-Shield All Weather Coating: A Whitehall Exclusive Alumi-Shield - Protects against the harshest weather and environmental elements. Extends the product life and maintains the look and function.