This is a very sticky tape that holds onto the roofing felt really well. I have used cheaper products however they do not even hold well enough while the roofing is being repaired let alone standing the test of time. This has a backing tape which can be tricky to peel off but does make accurate applications easier in the first instance and there is a chance to realign (to an extent) before finally rubbing it into place. In the image below the bottom strip of insulation underlay has been done with superFoil and the second line with a less effective product, by the time I reached the third layer with super Foil, bits of the second layer had already become detached. Unfortunately I have laid the tiles before taking the next images.