They were built to destroy JL's W7 series drivers, and they look like they will. Each one weighs over 50 lbs and has 4" of excursion. The 10" driver has more than twice the displacement of the typical 15" driver! I need to find out if these subs can be used in sealed enclosures. If so, I'll build an enclosure for my HT system using one of these subs. It should require a much smaller enclosure than a 15" driver, and it'll move a lot more air.