First, the disclaimer, because the Wannabe Lawyer Cat demanded it: This is not a medical grade mask. The CDC says that cloth masks are extremely helpful, though. No warranty is expressed or implied.
This mask is not sterile, though it was washed after assembly. You should wash it before you wear it the first time. Wash regular cycle with warm or hot water and tumble dry. You may find it doesn’t tangle up with the rest of your clothing if you use a pillowcase or lingerie (mesh) bag.
The mask contains a filter pocket, so you may add whatever filter you wish. One flannel filter is included, and it should be washed daily. The CDC says you can use a blue shop towel, a coffee filter, or a paper towel (you might want to use a double layer of that). Check with their web site for up-to-date recommendations.
A DIY filter is easy to make. Use the flannel as a template, or cut a 5.5” x 3” square of your preferred material. You may want to cut a template out of card stock (thin cardboard like a cereal box will do) so you can use it over and over.
There is a channel on the back (above the filter pocket) with a removable nose wire. You may want to remove the wire for washing, as it can get bent out of shape. You may replace it with your preferred material for a nose wire, or remove it completely.
Your mask will either come with ties or elastic, depending on your order. The elastic is untied so you can fit it better to your face. I will tie them in advance if you ask, but I can't guarantee the fit.
Any questions? Let me know at email@example.com.