Shurtape SF-682 HVAC Grade Duct Tape is a Shurflex contractor-grade metalized cloth duct tape used for air-tight and moisture-free sealing, seaming and joining of aluminum-backed flex ducts and metal ducts. The metallic coating put on the tape gives it a chrome look and feel. Shurtape SF-682 Duct Tape is the same tape as SF-683, but without the printing on the tape.