I bought one of the original SVS subs a few years ago. They had an upgrade driver available and I jumped on it, and this driver has been sitting in the box ever since and is in perfect condition. I think it is an "ISD" driver, I don't have the specs, but Tom from SVS said that if anyone needs any info regarding the driver to email him, he can help you out. $60 and $10 shipping to 48 states. See my ebay feedback, bphawkins.