GTMAT GT Seam Tape Aluminum Finishing Tape Automotive Sound Deadening - Sound Insulation Installation Includes: 2in Wide 30ft Roll of 4 Mil GT Seam Tape 30 In Length 2 Wide 4 mil Thickness Aluminum Tape With Release Liner Use GT Seam Tape to cover seams from your GT Mat installation creating one solid piece of sound deadening material. GT Seam Tape also makes a complete finished look to your installation.