Globes are 6 inches in diameter with a minimum neckless opening of 2.81 inches and a maximum opening of 4.5 inches. They are one piece injection blow molded, water and shatter resistant with UV inhibitors to help prevent yellowing. This is a custom opening and can not be returned. 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.