Check ebay item# 252857795076. It's the cheap Chinese version of the 14mm Arizer male joint. I sterilized it when I received it and never had an issue. I can't find the 1-pack anymore, which I got for $5 last year. This listing is for a 2-pack. If you want the genuine Arizer stem there are some sites out there that sell them and there are a few different styles of stems to choose from. I got this one so if I feel like it, I can hook it to my bong that has a 14mm female joint.
Then you'll need to go to your local hardware store and get some drinking water grade clear "whip" tubing and find the right diameter that will let you insert the Alfa mouthpiece and the Arizer stem, which are the same diameter - that's what allows the mod to work. I cut the tubing down to approximately 1.5cm long and used it to merge the mouthpiece and stem together. Works like a champ. I never use the Alfa without it unless I'm in stealth or snowboarding mode, which I'm usually not. I love this setup. Cooler vapor, and no plastic taste or smell whatsoever, I taste nothing but my herbs.
If you don't want to do this mod, I've found that putting a chunk of organic cotton inside the Alfa MP reduces the heat on your lips significantly while simultaneously smoothing out the vapor, if youd rather stay stock.
I run both the cotton and the glass and love it. With those mods I have yet to find another portable that makes me want to shelf this thing for good, not even my awesome Ti Vapcap that's taking over the world right now.