Masks fit over the nose and mouth but don't make a tight seal the way that respirators so. Masks that take replaceable filters can provide significant protection but some of the inhaled and exhaled air will still make it around the mask and therefore not get filtered. A good way to evaluate the effectiveness of your mask is to take the sunglass-test: put on the mask and a pair of sunglasses and then walk up a flight (or a few flights) of stairs to get your heart rate up. If the sunglasses fog up, it means that air is flowing around your mask and this can be dangerous in high-risk environments (more about this in the next Pearl). These masks are fine for outdoor activities like hiking or brief excursions to well-ventilated stores to pick up a few items and they do offer protection against larger droplets that might hit your face if someone sneezes or coughs on you but they are not sufficient for higher-risk environments like a shared office, busy cash register, or an hour of shopping at a place like Costco.
Wraps are typically made of cloth. They can be wrapped around the face and head more than once to provide extra layers of protection. They are often more comfortable to wear than respirators or masks and can make a better seal around the nose and mouth than many masks. Wraps made of a tightly weaved cloth (like flannel) can offer better protection than most masks and have the advantage of being washable.
The Bottom Line: I recommend everyone have at least one respirator and one mask or wrap in good condition. We need to have a face-covering on at all times when we are around people who are not members of our households including close friends and relatives. At my office, we sell respirators from O2 Canada which have a higher efficiency rating and are more comfortable for long term wear than traditional N95 respirators. If you are interested in purchasing one, let us know.