Yes, a polyuerathane glue, that is what it says on their website. I just picked up this stuff a few days ago at the local hardware store.I found some info on the site... they said don't get it on your hands. And don't worry, the stains will wear off in a few days!
In the past, I had used yellow carpenter wood glues for speakers, and they seemed more than strong enough for the job. But I like the gap filling quality of this glue, even if the foamed glue in the gap adds no strength... it would make the joint airtight.