The Comfit Mouthpieces from SDI Diagnostics fit their full line of Spirometers. This mouthpiece is disposable, made of latex-free pliable rubber to eliminate allergic reactions. Designed with a center support to keep air flowing freely. The rims dip so that the frenula can be accommodated.

This disposable mouthpiece is a low-cost alternative to rubber mouthpieces.  Leak proof seal and center column to prevent airflow obstruction.  Fits most spirometers.