| a) | mountpieces – material and the final mouthpiece is evaluated by the State medical institution in Prague from date 6th November 1998.
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| b) | Occasional insertion of the glass tube unprotected by the mouthpiece is evaluated by the National hygienist of the Czech Republic from date 26.3.1997.
A part of the tube inserted into the mouth does not include any possible harm for human organism.
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