These are the Original Sham Sweatbands not cheap knock offs. They are made with a special foam core that has been tested to hold 1/4 cup of water; due to this construction the sweatband is machine washable but must be air dried. The special material used has HGT (Head Gripping Technology) built right in. As the material gets wet, it doesn't slip like terry cloth does, it actually grips the forehead and holding your mask in place better, especially late in the game.