Unna-Z Unna Boot Dressing with Zinc maintains a moist healing environment and provides light compression for venous leg ulcers. This Unna-Z Unna Boot bandage is impregnated with zinc oxide. It can be left in place for up to 7 days depending on the amount of drainage. Latex Free. This Unna-Z does NOT contain calamine. White in color. Available in 2 sizes: 3" x 10yds and 4" x 10yds.