West Penn AQ227-SEG-59 12 Gauge Aquaseal Wire
West Penn 12 gauge Aquaseal wire is obviously designed to be impervious to water and moisture, and has a PVC outer jacket. PVC is much more resistant to water than is polyethylene, but is also stiffer and harder to bend. So right away, if you know you'll need to make some tight turns when running speaker wires, this may not be your best choice. The black color may also not be perfect for situations where the wires are visible.
That being said, if your setup will require that your wire runs are exposed to extreme conditions over long distances, you will want to consider using West Penn's speaker wire. The conductors are 12 gauge copper, and the cables are rated for use from -20C to 60C (-4 to 140 degrees Fahrenheit).