These grommets work for Large Egyptian vases which have the 2 inch opening such as Khalil Mamoon and similar Hookah Vases. They are made to fit all Large Egyptian stems such as Khalil Mamoon, Omar, Shika etc.
Due to the hand-made nature of Egyptian products, there will be some variances in vase sizes hence the ridge design to allow more flexibility in the fit. This 4 Ridge design tends to fit better on vases which are a little on looser side (exactly 2 inches). If you want a grommet to fit a vase which has a diameter of a little under 2 inches and tends to be on the tighter side go for The 3 Ridge Design which tends to have little thinner walls.