Top quality, Venture brand foil. 108 feet long. 1.5mil thick. 3/8" thick. Use black backed foil on clear and transparent glass, mirrors and bevels. Its black, non-reflective backing matches well with black patina. Many of our customers enjoy 1.5mil thick tape for its heavy weight and durability. Extra-wide, use with thick glass or when the strength of your project is important. Telling your foil apart is easy with Venture Foil Tape. The inside ring for 1.5mil is always red or dark pink for easy identification. Project image from "300 Stained Glass Cabinet Door Designs" book #6078. 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