Can anyone point me in the right direction of what number or code is the correct one for fiberglassing/gelcoating? I haven't been successful online and my local store wasn't much help. I came across 2: 1) N95 2) P100. I am more concerned with the fumes vs dust. Am I correct that when sanding fiberglass I can just use the dust style masks and save the cartridge style mask for when there is uncured product (ie vapours)? What I found was N/R/P code refers to resistance to oil but not sure how this translates into vapour protection. I am currently fiberglassing/gelcoating and want vapour protection. I would also like this to protect when using varathane type products. I did buy 1 product (not used yet), it's codes were: Stanley NIOSH approved MC/P100 Class. The other available was a N95 (inferior I believe). Also, what are the life expectancies for the cartridges? Is it based on how much they are used or how long they are out of the package exposed to air? The instructions are classic....replace based on the recommended chart. Trouble is, they don't bother to give a chart. I would rarely be using a respirator and would rather not drop $30 for replacement cartridges each use. (Cartridges with mask was $50). Thanks in advance.