Each 3.25" square filter is made of soft fabric with an antimicrobial treatment on the side touching the skin. The fabric is impregnated with activated carbon, which faces the underwear or the pants and has a vast surface area for bad odors to adhere to and get neutralized. Two adhesive strips are strategically placed so you know which side is which. And at around 1/32" thick, you will never know it's there. Now with improved adhesive!