The best $ you can possibly spend. Imagine triple wide whiteout correction tape
roller, now replace that white out tape with double sided tape (more of a gel).
Now remove an conception of this working improperly in any way and you have this
little piece of black magic. Just buy this.
Currently using to seal my envelopes. At first it was tricky, since I've never
used this product, but it was easier by the third. also be sure to store it in a place were it won't get warm, it might ruin it.