If your perc has a 14mm female you can do this. The Alfa mouthpiece and this Arizer 14mm gong stem are being held together by a short piece of food grade tubing (can't remember the inner diameter, but it's perfectly snug). The Alfa MP slides halfway into the tubing while the other half of the MP slides into the Alfa. I got the $4 stem from China on ebay. I never use the Alfa without it.