Masks have a pocket sewn into the back for a PM2.5 filter to be inserted. Even if you do not use a filter, this adds another layer of fabric to help slow spread of particles.
Wash it regularly in washing machine to sterilize.
Thin metal wire is sewn into mask for a custom fit over the bridge of your nose.
Soft, stretchy elastic ear loops can be tied shorter for a custom fit. Hopefully that will help your kids from taking them off!