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. Please note that the size and diameter of the grommets may vary slightly.