These are special eition of Egyptian Jumbo Bases. The diameter of the opening is 3.7cm or 1.75 inches, which fits a size 30 vase gasket. However, they alwats vary, same as KM base grommets. If you are ordering this base and a KM grommet make your instructions clear in the comments section that you would like them to match. KM stems are all the same, it’s glass and grommets that vary. This vase is tear drop shape and comes in black and Gold stripes with Paraonie designs.