Selecting a glass cloche is a good choice, for the elegant look of your display. Glass cloches come in 2 pieces (Glass dome and a wooden base), with the glass dome lifting off the base. When deciding how wide of a dome (inside) you need, always use the 2 inch rule. Measure the total width of the item you wish to display, then add 2 inches. This would be the "diameter" of the base you would need. It will give your display item 1 inch on either side, to prevents a "cramped" look, and makes a nicer viewing display piece. Most bases are wider then then diameter listed, with usually a 1" lip beyond the "groove" in the base. This width does get smaller, the smaller dome your purchase. When deciding how tall you need your dome to be, again, use the 2 inch rule. Measure the total height of your display object, and add 2 inches. Cloches curve on the top, and this will help prevent your object top from getting placed in the curving area. You may have to go above the 2" rule on top, to find a height you need.