The Canadian promo cassette (or cassingle) features the 7" version of Rubberband Girl twice, along with the 12" version of Rubberband Girl. All three tracks repeat on the second side. As far as I know this promo cassette is the only one that features the 12" version of Rubberband Girl.
The absolute beauty of this promo is how cheap it actually looks, especially when it comes to the insert. If the insert looks cheap and nasty, I can assure you it does look just as bad in person. It's pretty sad to think that this is an official promo release, but it is. The insert is nothing more than coloured, double-sided paper with some basic company info and a listing of the contents. You can see how nice and straight everything was originally printed, especially on the outer portion of the insert. Absolutely no thought or care went into the design of this.
The cassette is pretty standard as you can see. This one doesn't turn up often, but it's not rare and it's not worth going after either. Don't bother wasting your time on this one.