We purchased these patches to repair a crack in our acrylic shelled hot tub. The crack was about the size of a dime in the shape of an "X". Normally a complete repair for this kind of shell is done through a resin application but we wanted to try these first since the crack is inconspicuous and these patches are clear colored. These patches are available on Amazon at the same price but delivery would have taken 2 weeks. Walmart offered these with a 3-day delivery window and they arrived just as promised. You get two large squares and two rectangular pieces in each pack. For our use, I was able to cut a patch from a rectangular piece, slightly larger than the crack we were repairing. Unlike Gorilla or Flex Seal tapes, these are fairly thin, and easy to work with.
After draining the hot tub, we cleaned the area with alcohol and applied the patch. The directions say to wait 24-48 hours before refilling the tub but to be on the safe side, we waited an extra day before refilling the water. the bond is immediate so be careful that you place it exactly where you want it on the first try. Our only concern was maybe the chemicals in the water or the higher temperatures would degrade the patch but after a week, no leak so far! Even if the patch has to be reapplied when cleaning and refilling the hot tub, the purchase was well worth it. I would recommend them for this use.