Allevyn Heel dressing has been designed to absorb exudate with three part steps. The first is the wound contact layer that allows the exudate to pass thru it. The second part is called the hydrocellular core, which holds the exudate in a microscopic structure, and the last part is the breathable outer shell that allows the exudate to evaporate away from the dressing. In-vitro studies and clinical experience, both Allevyn Heel dressings can stay in place for up to seven days, depending on the amount of exudate. The Allevyn Heel dressing by Smith and Nephew promotes early healing due to moist wound environment, that the secret.