Top quality, Venture brand foil. 108 feet long. 1mil thick. 7/32" wide. Standard width, 1mil thick copper foil is easier to fold down over the edges of your glass than standard 1.25mil tape. Telling your foil apart is easy with Venture Foil Tape. The inside ring for 1mil is always purple for easy identification. Project by artist Beth Kauffman. From "Illuminations" book #5997. Delphi Tip: Choosing the Correct Foil When using transparent glass and bevels, choose your foil based on the color of your solder seams. Choose copper backed foil if using a copper patina Choose black backed foil if you are using black patina Choose silver backed foil if you are leaving your solder silver