Recently there was a company on the web who was trying to market generic mouthpieces for the Bodygem and Medgem Indirect calorimeters. They were also claiming to be authorized distributors for the Bodygem and Medgem. Microlife Home Medical Solutions, the manufacturer of the Bodygem and Medgem was successful at getting this company to shut down its website. What makes the Microlife mouthpiece unique is the microbial filter built into each mouthpiece. Contact Health & Fitness Network for the efficacy document on the mouthpiece. The mouthpiece is intended for use one time.