Although in many places on the Internet we can find information that it is an "impenetrable tube", in fact even the manufacturer states that it is an "extreme puncture resistance" tube. Its puncture resistance comes from the fact that a special liquid on the inner wall of the tube floods the puncture hole so effectively that it will stop escaping air quickly, and we can safely reach our destination. At least this should be the case in most cases and with relatively good and undamaged tires.
Considering the price of this inner tube, i.e. about PLN 35-45 (depending on its diameter and width and the type of valve), our assessment is definitely positive and we conclude that it is worth buying, but you cannot count on it to protect us with cheap or very old tires. Therefore, it is also worth investing in tires that are more important, choosing those with the highest durability and puncture resistance.
[you can read more here: https://www.forumrowerowe.org/topic/99327-detki-michelin-protek-max-kolejna-rewolucja/ - especially posts # 9 and 10]
