Antibacterial Foam Dressing McKesson 4 X 4 Inch Without Border Waterproof Film Backing Nonadhesive Square Sterile #4940Features Sterile, non adhesive wound dressing impregnated with PHMB Features polyhexamethylene biguanide (PHMB) substance which kills and inhibits the growth of bacteria Absorbent dressing designed for moderately to heavily exuding wounds Maintains effectiveness against a broad range of gram positive and gram negative microorganisms including some multi drug resistant strains such as MRSA In vitro testing demonstrated dressings to be effective against