DuoDerm Signal - Square Hydrocolloid Dressing absorbs fluid and acts as a barrier against bacterial, viral, and external contamination without damaging newly formed tissue. When the fluid appears as a bubble moving toward the indicator line, it is time to change the dressing. The border thins at the edges to help prevent roll-up, making it more comfortable to wear. This flexible wound dressing from ConvaTec encourages moist wound healing and provides the convenience of a change indicator.