Review on Respirator 3M 7502 size M by Micha ochowski ᠌

The most comfortable mask I've ever worn; the adjustable straps mean it doesn't press or rub. Filters are costly (about a third of the cost of a mask), but the benefits of having them—no odors, no dust getting in, and easy breathing—more than make up for the initial investment. Pre-filters, which may be installed for around $100 for a pair, significantly increase the filters' service life. Overall, I think this mask is well worth the price and would be a good investment if you spend a lot of time in smelly or dusty environments.