It's basically a scotch tape -- clear, thin, adhesive on one side -- but it doesn't come in a dispenser. You don't need one. It tears perfectly straight.
But wait, there's more! Once you've torn yourself a convenient piece, you don't need to worry about letting the remainder fall back against the roll. The sides of the tape are serrated, making it easy to start peeling a new piece. And, because the tape only tears crosswise to the roll, you never get into that sad situation where the tape sticks to itself and you get an ugly narrow strip.
Utter genius. But did we expect anything less from the good folks at Duck?