confused about power cable specs

I purchased a dual amp kit for my truck but the specs on the cable have me a little confused. Here is the cable http://sonicelectrnix.com/item_7280_e2+by+Scosche+E3200.html It says 15.5mm but the only thing that could be 15.5mm is the OVERALL diameter of the wire. The cable does however appear to be about .375 inches so I'm gonna say it's 0 gauge, the 9.5mm stuff looks to be about .25 Has anyone used this cable? I haven't opened it even though it LOOKS okay. Thanks

0AWG wire is 8.25mm (0.325") conductor diameter. Support the12volt.com

Thanks. I've read that but still don't know why it would be called 15.5mm wire. Isk

Note: Many companies claim their wire is 0 gauge or 4 gauge when in reality it is 2/3 instead of 0 or 5/6 gauge instead of 4 gauge with more plastic insulation to present an illusion of 0 or 4 gauge. Scosche did not want to make a false representation of their quality product so they specify their wire in millimeters, not the standard gauge system. We have decided that to present fair competition to the likes of "house brand" wire, and other unfair manufacturers which label their 0 or 4 gauge wire as such when it is less wire than what is included in the E3200. Above taken from page you were looking at. I guess they were trying to be more realistic in the way they represented their wire.