DuoDERM CGF (Control Gel Formula) Border Hydrocolloid Dressing, Sterile. DuoDERM CGF Border dressing incorporates a unique ConvaTec hydrocolloid formulation that distinguishes it from other hydrocolloid dressings. It can be used for 'hard-to-dress' areas. The dressing features a wide outer foam border that does not require additional taping. DuoDERMCGF Border dressing is indicated for use on dermal ulcers including full-thickness wounds, pressure ulcers (Stage II-IV), leg ulcers, superficial wounds, partial thickness burns and donor sites.