These are the best soft touch hospital grade inhalation Cannulas for our Hydrogen Inhalation machines (not for Portable Inhaler Adapter). These are non-crimping flexible tubing Soft-Touch nasal Cannulas with standard universal connector tips and curved, non-flared nasal prongs that minimize irritation and soreness when worn for hours at a time. Each Cannula is 7 feet long (2.1 meter) and are long lasting. We recommend you change your Cannula every 60 – 90 days depending on how often you use our inhalation machines. Comes in convenient 4 Packs. It is recommended not to share a Cannula for sanitary reasons and avoid sharing others by mistake by writing name on masking tape and wrapping around tubing.