The product video you should definitely once (ideally every six months) See, in order to ensure the proper use of the mask. The use is well explained, the application is easy and understandable.
The filter change who sees prolongs the life of the mask after 8 years to 16 years from a little tricky, but seems to be good to accomplish.
Whether the mask now actually works, I can not say (thankfully) and I hope that this case does not occur.
But to have alone this (admittedly expensive) fire guard in the house, gives me personally a secure feeling.
