The Arizer Air Mouthpiece is the black tip on the aroma tubes for the Air and Air 2. It is not compatible with other aroma tubes found in the Arizer accessory lineup. This mouthpiece screws on, and cools the vapor well for these shorter aroma tubes. Although the mouthpieces only fit the Air and Air 2 aroma tubes, once assembled, the tubes also fit the Solo and Solo 2 vaporizers. Glass aroma tubes are a big reason Arizer vaporizers are known for pure taste.