Bests & Worsts Reviews from Amazon

These are genuine 3m products. Multi gas cartridges have service life of 6 months once you open the original packaging. They also have to be stored in an airtight bag or box because they will absorb contaminants from the environment. I was bummed to find a tiny hole in the packaging which makes the cartridges contaminated and shortens the service life by a lot. So returned and ordered an exchange. Quick note for those who keeps saying the cartridges are expired. Please know the expiration date is on the outside of the package which is 5 years from date of manufacturing. The date you see on the cartridges itself is the born on date, meaning the date they were actually made. Do not confuse the born on date with expiration date on the OUTSIDE of the package.