7/8 male fitter to the base. No cracks by the collar. The item "VICTORIAN OPALINE YELLOW GLASS OIL LAMP FONT, perfect 1½ fitter" is in sale since Tuesday, October 19, 2021. This item is in the category "Collectables\Lamps, Lighting\Lamps".The seller is "goodrubbish" and is located in Plymouth. This item can be shipped worldwide.