Does what it says it would.
Crutchfield Customer Review (What's this?)
Works as intended. You'll have to be the judge whether it is worth the money or not, but it will eliminate rattling and boominess you may get from your floor or walls (boominess from a cheap sub will remain as that's a different issue than I was fighting). I am using on a very high quality sealed SVS sub, the SB12. At high volume, there was a boominess being caused from the walls and subfloor (sub is along wall, above basement on very short berber carpet). I knew the sub should be capable of very tight base at any volume. Figured I'd try and return if it didn't work. Well, happy too say it did. The sub can now be turned up to hearing loss inducing levels and is as tight as can be. Needless to say at my normal lower listening levels problem is resolved forever. i think the base at these lower listening levels are enhanced as well. There could be DIY solutions out there but figured I'd spend the money on an SVS engineered solution to my SVS sub. Well done. Highly recommended.