... CE ,ISO13485 3. anti-crush tube,non-toxic PVC,medical grade,flexible. nasal oxygen tube helping breathing oxygen1 ... .Made of non-toxic PVC,medical grade ,tubing color is green or transparent2 ... your choice, anti-crush 3.Different length available,with 2 connectors to match wide range of respiratory ... texture gives users' more comfort Pure PVC Nasal Cannula with oxygen tubing