The Grapes Door Knocker is cast in solid brass and highlighted in green patina. Brass and bronze are copper-based alloys. The yellow brass alloy used in many of Michael's designs contains 70% copper and produces a warm, traditional brass look. Red bronze contains almost 85% copper. This additional copper content gives the bronze alloy its rich, reddish undertone. The mirrored finish of polished brass and polished bronze is achieved through varying degrees of sanding and buffing. Michael uses these techniques to highlight or accent the raised areas on a piece. Each Doorknocker is hand polished and then the knocker is then coated with a clear lacquer to protect the original polished finish. Michael Healy has signed this Grape Cluster Doorknocker in the mold, confirming its authenticity and quality craftsmanship.