Since people are mentioning problems putting the self-adhesive foam in place: I cut longer than needed. Then I leave the paper backing in place for a couple of cm at each end. Then I remove 3 or 4 mm of backing every cm or so. Working from the center of the slot out, the remaining backing provides rigidity and the exposed part provides adhesion as the foam is tamped into place. When I get to each end (which still has backing on), I just remove that backing and press the last bit of foam into place. It's worked very well for me on several cameras: fast, friustration-free, and reliable.