Globes are clear acrylic, one piece injection blow molded with 3.5 inch minimum opening and a 5.5 inch maximum opening. This is a custom cut and is not returnable. Please see diagram. To request a custom opening, please enter the opening desired in the comments section at the bottom of the checkout page, or call 800-665-3594. If no custom opening is indicated, the globe will be sent with the minimum opening indicated in the description.