Kendall™ AMD antimicrobial foam dressings have been developed to support your efforts in managing both moisture and bacterial balance. The dressing is an open cell polyurethane foam dressing and is impregnated with 0.5% Polyhexamethylene Biguanide (PHMB), a highly effective, low toxicity antiseptic. The dressings are effective against gram positive and gram negative bacteria. They also work against fungi and yeast. 4" x 4" (10.2 cm x 10.2 cm).