Duck brand flex foil tape combines both the excellent sealing and protective benefits of aluminum with the superior adhesion of Duck brand duct tape. This UL181 B-FX listed silver adhesive tape is approved for use on flexible air ducts and is rated for flame spreads and smoke development. For use with a temperature range of -35 to +260-Degree (Fahrenheit), the flex foil tape has application characteristics and ease of handling similar to pressure-sensitive tapes.