Hartmann Hydrofilm, 20 x 30 cm, 1 Box of 10 Pieces. Transparent film dressing. The transparent film dressing for safe wound protection. • Transparent film dressing. MDD: As protection from secondary infections and from physical irritants in dry, primary healing wounds, in almost healed epithelial wounds and for securing catheters and cannulas; perfect for covering gel forming calcium alginate dressings, such as Sorbalgon.