The masks I made using this kit were double sided cotton with interfacing between the two layers, i used a pleated pattern, i have put instructions up on my blog of the masks i made, as i found it more comfortable style, this is only suggestion.
This fabric is not of a medical grade and contains no filters.
This pack contains enough fabric to make 5 face masks, the mask would be double sided with the tightly woven cotton fabric, interfaced and elastic to fit around the ears. ( i did manage to get 6 out of this fabric as its slightly wider )
The intefacing I have chosen is soft and durable, as this product will be washed on a regular basis, this interfacing has a high level of resistance againt repeated care treatments. The interfacing has good adhesion, iron on to the fabric with a medium iron for approximately 6-8 seconds then let it cool before sewing the rest of the mask together.