Isle of Man - First 20 Years of Proof Silver Cat Crowns - 1988 - 2007 - Cherrywood Presentation Case - COA - It has taken us years to put together this complete set of the first twenty years of Isle of Man Proof Silver Cat Crowns. Each one of the twenty crowns in this set was minted to proof specifications from one troy ounce of .999 fine silver. We are pleased to offer this set in a beautiful cherrywood presentation case with an accompanying Certificate of Authenticity.