Like I said, I've been wearing the same N95 for a long time. But, living in a rural area and sticking close to home I don't have to wear it but a few times a week. The N95 I have has a thin band of metal probably 3/8" wide that can been to conform to the nose. It indeed seals very well, though sometimes I would still have my glasses to fog up with the N95, though.
The box of *Chinese* manufactured cheap masks have a much, much smaller piece of metal(?) that can be molded to conform to the bridge of your nose. That seems to work fairly well. BUT, around the face the masks *do not* seal nearly as well as the N95. There can be gaps and the mask themselves, having ear-loops, don't seem to fit as snug as the N95 mask with it double, around-the-head straps.
I'm considering ordering in some of the KN95 masks. They may not have the filtration capability of the N95 or they may have...I think the difference is the act of "certification". One is certified to filter certain particles but the other hasn't though it may well be able to. Or, maybe I just imagined I read that somewhere...??? But, it seems the KN95 masks would at least seal better around the perimeter than the plain-jane masks.
Btw, just had a COVID-19 test yesterday, should get results back Saturday. I'd been feeling crappy for a week with different symptoms. Sudden onset last Thursday night. So far no loss of taste/smell, little to no fever (high was like 99.5F), but some chest discomfort up high, sore throat, headache, aches. I'm thinking more along the lines of either allergies or URTI. But, I've got a wife, daughters and granddaughters, and friends I want to be careful around. But, this knocked me out of an orthopedic appointment and my annual cardio appointment....both rescheduled.<sigh> We'll see....