These are non-medical PM 2.5 filters. These have 5 layers. Anti-sticky cloth + filter cloth + activated carbon layer + filter cloth + anti sticky cloth. These can not be washed. Recommended to use for up to 7 days per filter. Filters can be inserted in our Infinity 2+5 Layer Filter Masks, Form Fit Face Masks, Infinity LED Face Masks & 2/3 Layer Gaiters.