ConvaTec DuoDERM® Extra Thin Hydrocolloid Dressing Strip 3" x 3" Square Translucent Backing, Occlusive DuoDERM® Extra Thin dressing is a hydrocolloid dressing indicated for the management of lightly exuding wounds. It combines a unique ConvaTec hydrocolloid formulation that distinguishes it from other hydrocolloid dressings and a vapor-permeable outer film to provide an occlusive moist environment.