Holds well. Delivered width is closer to 3-3/4" rather than 4". 15 mils thick.

Tape sticks well and is flexible. It does not actually bond to the liner but rather has a strong adhesion, so you are able to pull it off and reposition it, albeit with quite a bit of pulling. Take your time and concentrate while lying it down to minimize air bubbles. Also be aware that when sealing around inside corners or bridging gaps, lay the tape without creating tension on itself or it will pull itself off and or up. That's the tradeoff for not bonding but if this stuff bonded like butyl rubber does to the liner, you would be in trouble if you put it down incorrectly or got off track while joining to pieces of liner. After putting down several hundred feet of this tape, I have no qualms stating that it is a high quality product that compliments the Silverback liner I used.

All Project products work very well. I am very happy with the results would highly recommend.

Great tape! Sticks well to the vapor barrier. Tip, use a blade not a pair of scissors to cut the tape. And wipe the area your going to tape with a cloth to get ride of the dust and dirt.

great stuff; adheres to more surfaces than any product I've had