The Hydrofera Blue Antimicrobial Foam Dressing 4 X 4 Inch Square Non-Adhesive without Border, Sterile Features: -A foam dressing containing two pigments, methylene blue and gentian violet, in -open-celled polyvinyl alcohol. (PVA) -Rapid wicking and exudate retention. -Assists in autolytic debridement. -Helps maintain a moist wound environment. 1 Dressing