I couldn't find mounting foam at any of my local craft stores so I turned to scrapbook.com as I have many times in the past. I now have all of my unmounted stamps on cling foam and am so happy with this product. It IS very sticky, but I know that my stamps will likely never come off the foam. Stamps cling very well to acrylic blocks, too.
I had unmounted red rubber stamps and very easily backed them with this product. It was so easy, in fact, that I took all my wood block mounted stamps off their mounts and turned them into cling stamps. Sure saves me a lot of space. Wouldn't hesitate to buy more.