From the site:
The BL Series fills the gap between the all out SPL monster and a solid daily driver. Featuring a solid pole piece and standard double stack motor structure as the foundation for a truly tough subwoofer, you can choose from a variety of options to custom tailor the sub for your exact application. With the addition of the pole chamfer or axial cooling channels along with the Daily option, you can bump up the subs thermal capacity for long term daily driving abuse. Looking for an ultra tough higher Qts SPL sub? Choose the SPL option, the extreme lead wire, one of the 8 layer aluminum flatwind voicecoils, add power, and let it rip. With head cracking upper bass and brutal low end, the BL handles the extremes with ease.
I saw what you mean with it going blank.. there must be some issues but it doesnt go on to say much more but normally it lists some of the T/S parameters for each size sub and the prices of the subs and their available upgrades