Description:This is an adapter for 9 mm. filter stems. It will fit 99 %. Many ask us if you have to use filter in a 9 mm. filter pipe and the answer is no. You can use it completely without anything or you can plug this adapter in. Some pipesmokers claim that you have a better airway in a 9 mm. filter pipe when you are not using a filter.TAX FREE: Please note that if you are an outside EU citizen the VAT (20%) will be deducted the listed prices when/if you finish your order.